diff --git a/src/cargo/core/package.rs b/src/cargo/core/package.rs
index 6f160db5334..a1fe7823787 100644
--- a/src/cargo/core/package.rs
+++ b/src/cargo/core/package.rs
@@ -102,6 +102,7 @@ pub struct SerializedPackage {
     links: Option<String>,
     #[serde(skip_serializing_if = "Option::is_none")]
     metabuild: Option<Vec<String>>,
+    default_run: Option<String>,
 }
 
 impl Package {
@@ -267,6 +268,7 @@ impl Package {
             links: self.manifest().links().map(|s| s.to_owned()),
             metabuild: self.manifest().metabuild().cloned(),
             publish: self.publish().as_ref().cloned(),
+            default_run: self.manifest().default_run().map(|s| s.to_owned()),
         }
     }
 }
diff --git a/src/doc/man/cargo-metadata.md b/src/doc/man/cargo-metadata.md
index 33951fddd69..3ef6e8d6884 100644
--- a/src/doc/man/cargo-metadata.md
+++ b/src/doc/man/cargo-metadata.md
@@ -180,6 +180,8 @@ The output has the following format:
             "categories": [
                 "command-line-utilities"
             ],
+            /* Optional string that is the default binary picked by cargo run. */
+            "default_run": null,
             /* Array of keywords from the manifest. */
             "keywords": [
                 "cli"
diff --git a/src/doc/man/generated_txt/cargo-metadata.txt b/src/doc/man/generated_txt/cargo-metadata.txt
index 8dcd2227e81..97a1940f660 100644
--- a/src/doc/man/generated_txt/cargo-metadata.txt
+++ b/src/doc/man/generated_txt/cargo-metadata.txt
@@ -175,6 +175,8 @@ OUTPUT FORMAT
                        "categories": [
                            "command-line-utilities"
                        ],
+                       /* Optional string that is the default binary picked by cargo run. */
+                       "default_run": null,
                        /* Array of keywords from the manifest. */
                        "keywords": [
                            "cli"
diff --git a/src/doc/src/commands/cargo-metadata.md b/src/doc/src/commands/cargo-metadata.md
index b59e2638715..7d856a49aa7 100644
--- a/src/doc/src/commands/cargo-metadata.md
+++ b/src/doc/src/commands/cargo-metadata.md
@@ -180,6 +180,8 @@ The output has the following format:
             "categories": [
                 "command-line-utilities"
             ],
+            /* Optional string that is the default binary picked by cargo run. */
+            "default_run": null,
             /* Array of keywords from the manifest. */
             "keywords": [
                 "cli"
diff --git a/src/etc/man/cargo-metadata.1 b/src/etc/man/cargo-metadata.1
index 2c20cc7880b..dfe79583c45 100644
--- a/src/etc/man/cargo-metadata.1
+++ b/src/etc/man/cargo-metadata.1
@@ -177,6 +177,8 @@ The output has the following format:
             "categories": [
                 "command\-line\-utilities"
             ],
+            /* Optional string that is the default binary picked by cargo run. */
+            "default_run": null,
             /* Array of keywords from the manifest. */
             "keywords": [
                 "cli"
diff --git a/tests/testsuite/alt_registry.rs b/tests/testsuite/alt_registry.rs
index 336e978ffd8..dd08e3a517c 100644
--- a/tests/testsuite/alt_registry.rs
+++ b/tests/testsuite/alt_registry.rs
@@ -829,6 +829,7 @@ fn alt_reg_metadata() {
                         "publish": null,
                         "authors": [],
                         "categories": [],
+                        "default_run": null,
                         "keywords": [],
                         "readme": null,
                         "repository": null,
@@ -885,6 +886,7 @@ fn alt_reg_metadata() {
                         "publish": null,
                         "authors": [],
                         "categories": [],
+                        "default_run": null,
                         "keywords": [],
                         "readme": null,
                         "repository": null,
@@ -909,6 +911,7 @@ fn alt_reg_metadata() {
                         "publish": null,
                         "authors": [],
                         "categories": [],
+                        "default_run": null,
                         "keywords": [],
                         "readme": null,
                         "repository": null,
@@ -933,6 +936,7 @@ fn alt_reg_metadata() {
                         "publish": null,
                         "authors": [],
                         "categories": [],
+                        "default_run": null,
                         "keywords": [],
                         "readme": null,
                         "repository": null,
@@ -982,6 +986,7 @@ fn alt_reg_metadata() {
                         "publish": null,
                         "authors": [],
                         "categories": [],
+                        "default_run": null,
                         "keywords": [],
                         "readme": null,
                         "repository": null,
@@ -1019,6 +1024,7 @@ fn alt_reg_metadata() {
                         "publish": null,
                         "authors": [],
                         "categories": [],
+                        "default_run": null,
                         "keywords": [],
                         "readme": null,
                         "repository": null,
@@ -1115,6 +1121,7 @@ fn unknown_registry() {
                   "publish": null,
                   "authors": [],
                   "categories": [],
+                  "default_run": null,
                   "keywords": [],
                   "readme": null,
                   "repository": null,
@@ -1139,6 +1146,7 @@ fn unknown_registry() {
                   "publish": null,
                   "authors": [],
                   "categories": [],
+                  "default_run": null,
                   "keywords": [],
                   "readme": null,
                   "repository": null,
@@ -1176,6 +1184,7 @@ fn unknown_registry() {
                   "publish": null,
                   "authors": [],
                   "categories": [],
+                  "default_run": null,
                   "keywords": [],
                   "readme": null,
                   "repository": null,
diff --git a/tests/testsuite/features_namespaced.rs b/tests/testsuite/features_namespaced.rs
index 9922674b3e7..0c3022c8dd3 100644
--- a/tests/testsuite/features_namespaced.rs
+++ b/tests/testsuite/features_namespaced.rs
@@ -766,6 +766,7 @@ fn json_exposed() {
                       "publish": null,
                       "authors": [],
                       "categories": [],
+                      "default_run": null,
                       "keywords": [],
                       "readme": null,
                       "repository": null,
diff --git a/tests/testsuite/git.rs b/tests/testsuite/git.rs
index bd3718e7acd..46830457fc0 100644
--- a/tests/testsuite/git.rs
+++ b/tests/testsuite/git.rs
@@ -3081,6 +3081,7 @@ fn metadata_master_consistency() {
                   "publish": null,
                   "authors": [],
                   "categories": [],
+                  "default_run": null,
                   "keywords": [],
                   "readme": null,
                   "repository": null,
@@ -3118,6 +3119,7 @@ fn metadata_master_consistency() {
                   "publish": null,
                   "authors": [],
                   "categories": [],
+                  "default_run": null,
                   "keywords": [],
                   "readme": null,
                   "repository": null,
diff --git a/tests/testsuite/metadata.rs b/tests/testsuite/metadata.rs
index 87efa67fa96..a6545582e58 100644
--- a/tests/testsuite/metadata.rs
+++ b/tests/testsuite/metadata.rs
@@ -22,6 +22,7 @@ fn cargo_metadata_simple() {
                     "wycats@example.com"
                 ],
                 "categories": [],
+                "default_run": null,
                 "name": "foo",
                 "version": "0.5.0",
                 "id": "foo[..]",
@@ -119,6 +120,7 @@ crate-type = ["lib", "staticlib"]
             {
                 "authors": [],
                 "categories": [],
+                "default_run": null,
                 "name": "foo",
                 "readme": null,
                 "repository": null,
@@ -206,6 +208,7 @@ optional_feat = []
             {
                 "authors": [],
                 "categories": [],
+                "default_run": null,
                 "name": "foo",
                 "readme": null,
                 "repository": null,
@@ -309,6 +312,7 @@ fn cargo_metadata_with_deps_and_version() {
             {
                 "authors": [],
                 "categories": [],
+                "default_run": null,
                 "dependencies": [
                     {
                         "features": [],
@@ -361,6 +365,7 @@ fn cargo_metadata_with_deps_and_version() {
             {
                 "authors": [],
                 "categories": [],
+                "default_run": null,
                 "dependencies": [],
                 "description": null,
                 "edition": "2015",
@@ -400,6 +405,7 @@ fn cargo_metadata_with_deps_and_version() {
             {
                 "authors": [],
                 "categories": [],
+                "default_run": null,
                 "dependencies": [
                     {
                         "features": [],
@@ -464,6 +470,7 @@ fn cargo_metadata_with_deps_and_version() {
             {
                 "authors": [],
                 "categories": [],
+                "default_run": null,
                 "dependencies": [],
                 "description": null,
                 "edition": "2015",
@@ -605,6 +612,7 @@ name = "ex"
             {
                 "authors": [],
                 "categories": [],
+                "default_run": null,
                 "name": "foo",
                 "readme": null,
                 "repository": null,
@@ -698,6 +706,7 @@ crate-type = ["rlib", "dylib"]
             {
                 "authors": [],
                 "categories": [],
+                "default_run": null,
                 "name": "foo",
                 "readme": null,
                 "repository": null,
@@ -798,6 +807,7 @@ fn workspace_metadata() {
                     "wycats@example.com"
                 ],
                 "categories": [],
+                "default_run": null,
                 "name": "bar",
                 "version": "0.5.0",
                 "id": "bar[..]",
@@ -835,6 +845,7 @@ fn workspace_metadata() {
                     "wycats@example.com"
                 ],
                 "categories": [],
+                "default_run": null,
                 "name": "baz",
                 "readme": null,
                 "repository": null,
@@ -927,6 +938,7 @@ fn workspace_metadata_no_deps() {
                     "wycats@example.com"
                 ],
                 "categories": [],
+                "default_run": null,
                 "name": "bar",
                 "readme": null,
                 "repository": null,
@@ -964,6 +976,7 @@ fn workspace_metadata_no_deps() {
                     "wycats@example.com"
                 ],
                 "categories": [],
+                "default_run": null,
                 "name": "baz",
                 "readme": null,
                 "repository": null,
@@ -1031,6 +1044,7 @@ const MANIFEST_OUTPUT: &str = r#"
             "wycats@example.com"
         ],
         "categories": [],
+        "default_run": null,
         "name":"foo",
         "version":"0.5.0",
         "id":"foo[..]0.5.0[..](path+file://[..]/foo)",
@@ -1216,6 +1230,7 @@ fn package_metadata() {
             {
                 "authors": ["wycats@example.com"],
                 "categories": ["database"],
+                "default_run": null,
                 "name": "foo",
                 "readme": "README.md",
                 "repository": "https://github.com/rust-lang/cargo",
@@ -1293,6 +1308,7 @@ fn package_publish() {
             {
                 "authors": ["wycats@example.com"],
                 "categories": ["database"],
+                "default_run": null,
                 "name": "foo",
                 "readme": "README.md",
                 "repository": "https://github.com/rust-lang/cargo",
@@ -1367,6 +1383,7 @@ fn cargo_metadata_path_to_cargo_toml_project() {
                         "wycats@example.com"
                     ],
                     "categories": [],
+                    "default_run": null,
                     "dependencies": [],
                     "description": null,
                     "edition": "2015",
@@ -1453,6 +1470,7 @@ fn package_edition_2018() {
                             "wycats@example.com"
                         ],
                         "categories": [],
+                        "default_run": null,
                         "dependencies": [],
                         "description": null,
                         "edition": "2018",
@@ -1514,6 +1532,126 @@ fn package_edition_2018() {
         .run();
 }
 
+#[cargo_test]
+fn package_default_run() {
+    let p = project()
+        .file("src/lib.rs", "")
+        .file("src/bin/a.rs", r#"fn main() { println!("hello A"); }"#)
+        .file("src/bin/b.rs", r#"fn main() { println!("hello B"); }"#)
+        .file(
+            "Cargo.toml",
+            r#"
+                [project]
+                name = "foo"
+                version = "0.1.0"
+                authors = ["wycats@example.com"]
+                edition = "2018"
+                default-run = "a"
+            "#,
+        )
+        .build();
+    p.cargo("metadata")
+        .with_json(
+            r#"
+            {
+                "packages": [
+                    {
+                        "authors": [
+                            "wycats@example.com"
+                        ],
+                        "categories": [],
+                        "default_run": "a",
+                        "dependencies": [],
+                        "description": null,
+                        "edition": "2018",
+                        "features": {},
+                        "id": "foo 0.1.0 (path+file:[..])",
+                        "keywords": [],
+                        "license": null,
+                        "license_file": null,
+                        "links": null,
+                        "manifest_path": "[..]Cargo.toml",
+                        "metadata": null,
+                        "publish": null,
+                        "name": "foo",
+                        "readme": null,
+                        "repository": null,
+                        "homepage": null,
+                        "documentation": null,
+                        "source": null,
+                        "targets": [
+                            {
+                                "crate_types": [
+                                    "lib"
+                                ],
+                                "doc": true,
+                                "doctest": true,
+                                "test": true,
+                                "edition": "2018",
+                                "kind": [
+                                    "lib"
+                                ],
+                                "name": "foo",
+                                "src_path": "[..]src/lib.rs"
+                            },
+                            {
+                                "crate_types": [
+                                    "bin"
+                                ],
+                                "doc": true,
+                                "doctest": false,
+                                "test": true,
+                                "edition": "2018",
+                                "kind": [
+                                    "bin"
+                                ],
+                                "name": "a",
+                                "src_path": "[..]src/bin/a.rs",
+                                "test": true
+                            },
+                            {
+                                "crate_types": [
+                                    "bin"
+                                ],
+                                "doc": true,
+                                "doctest": false,
+                                "test": true,
+                                "edition": "2018",
+                                "kind": [
+                                    "bin"
+                                ],
+                                "name": "b",
+                                "src_path": "[..]src/bin/b.rs",
+                                "test": true
+                            }
+                        ],
+                        "version": "0.1.0"
+                    }
+                ],
+                "resolve": {
+                    "nodes": [
+                        {
+                            "dependencies": [],
+                            "deps": [],
+                            "features": [],
+                            "id": "foo 0.1.0 (path+file:[..])"
+                        }
+                    ],
+                    "root": "foo 0.1.0 (path+file:[..])"
+                },
+                "target_directory": "[..]",
+                "version": 1,
+                "workspace_members": [
+                    "foo 0.1.0 (path+file:[..])"
+                ],
+                "workspace_root": "[..]",
+                "metadata": null
+            }
+            "#,
+        )
+        .run();
+}
+
 #[cargo_test]
 fn target_edition_2018() {
     let p = project()
@@ -1543,6 +1681,7 @@ fn target_edition_2018() {
                             "wycats@example.com"
                         ],
                         "categories": [],
+                        "default_run": null,
                         "dependencies": [],
                         "description": null,
                         "edition": "2015",
@@ -1648,6 +1787,7 @@ fn rename_dependency() {
         {
             "authors": [],
             "categories": [],
+            "default_run": null,
             "dependencies": [],
             "description": null,
             "edition": "2015",
@@ -1687,6 +1827,7 @@ fn rename_dependency() {
         {
             "authors": [],
             "categories": [],
+            "default_run": null,
             "dependencies": [],
             "description": null,
             "edition": "2015",
@@ -1726,6 +1867,7 @@ fn rename_dependency() {
         {
             "authors": [],
             "categories": [],
+            "default_run": null,
             "dependencies": [
                 {
                     "features": [],
@@ -1871,6 +2013,7 @@ fn metadata_links() {
                 {
                   "authors": [],
                   "categories": [],
+                  "default_run": null,
                   "dependencies": [],
                   "description": null,
                   "edition": "2015",
@@ -2014,6 +2157,7 @@ fn deps_with_bin_only() {
                   "publish": null,
                   "authors": [],
                   "categories": [],
+                  "default_run": null,
                   "keywords": [],
                   "readme": null,
                   "repository": null,
@@ -2117,6 +2261,7 @@ fn filter_platform() {
       "publish": null,
       "authors": [],
       "categories": [],
+      "default_run": null,
       "keywords": [],
       "readme": null,
       "repository": null,
@@ -2159,6 +2304,7 @@ fn filter_platform() {
       "publish": null,
       "authors": [],
       "categories": [],
+      "default_run": null,
       "keywords": [],
       "readme": null,
       "repository": null,
@@ -2201,6 +2347,7 @@ fn filter_platform() {
       "publish": null,
       "authors": [],
       "categories": [],
+      "default_run": null,
       "keywords": [],
       "readme": null,
       "repository": null,
@@ -2243,6 +2390,7 @@ fn filter_platform() {
       "publish": null,
       "authors": [],
       "categories": [],
+      "default_run": null,
       "keywords": [],
       "readme": null,
       "repository": null,
@@ -2348,6 +2496,7 @@ fn filter_platform() {
       "publish": null,
       "authors": [],
       "categories": [],
+      "default_run": null,
       "keywords": [],
       "readme": null,
       "repository": null,
diff --git a/tests/testsuite/read_manifest.rs b/tests/testsuite/read_manifest.rs
index 24d855eb029..28bf6eed2a7 100644
--- a/tests/testsuite/read_manifest.rs
+++ b/tests/testsuite/read_manifest.rs
@@ -10,6 +10,7 @@ fn manifest_output(readme_value: &str) -> String {
         "wycats@example.com"
     ],
     "categories": [],
+    "default_run": null,
     "name":"foo",
     "readme": {},
     "homepage": null,
diff --git a/tests/testsuite/update.rs b/tests/testsuite/update.rs
index 8a4d589989f..33ca18c38b1 100644
--- a/tests/testsuite/update.rs
+++ b/tests/testsuite/update.rs
@@ -433,6 +433,7 @@ fn update_precise_first_run() {
     {
       "authors": [],
       "categories": [],
+      "default_run": null,
       "dependencies": [
         {
           "features": [],
@@ -485,6 +486,7 @@ fn update_precise_first_run() {
     {
       "authors": [],
       "categories": [],
+      "default_run": null,
       "dependencies": [],
       "description": null,
       "documentation": null,