diff --git a/bin/kuduSync.js b/bin/kuduSync.js
index 2bab775..098a85d 100644
--- a/bin/kuduSync.js
+++ b/bin/kuduSync.js
@@ -286,6 +286,14 @@ var DirectoryInfo = (function (_super) {
     DirectoryInfo.prototype.subDirectoriesList = function () {
         return this._subDirectoriesList;
     };
+    DirectoryInfo.prototype.isSubdirectoryOf = function (potentialParentDirectory) {
+        if(potentialParentDirectory == null || this.path() == null || potentialParentDirectory.path() == null) {
+            return false;
+        }
+        var thisPath = pathUtil.resolve(this.path());
+        var potentialParentDirectoryPath = pathUtil.resolve(potentialParentDirectory.path());
+        return thisPath.toUpperCase().indexOf(potentialParentDirectoryPath.toUpperCase()) == 0;
+    };
     return DirectoryInfo;
 })(FileInfoBase);
 var Manifest = (function () {
@@ -352,6 +360,9 @@ function kuduSync(fromPath, toPath, nextManifestPath, previousManifestPath, igno
     if(!from.exists()) {
         return Q.reject(new Error("From directory doesn't exist"));
     }
+    if(from.isSubdirectoryOf(to) || to.isSubdirectoryOf(from)) {
+        return Q.reject(new Error("Source and destination directories cannot be sub-directories of each other"));
+    }
     var nextManifest = new Manifest();
     var ignoreList = parseIgnoreList(ignore);
     log("Kudu sync from: '" + from.path() + "' to: '" + to.path() + "'");
diff --git a/lib/DirectoryInfo.ts b/lib/DirectoryInfo.ts
index 7254551..e1724e5 100644
--- a/lib/DirectoryInfo.ts
+++ b/lib/DirectoryInfo.ts
@@ -149,4 +149,15 @@ class DirectoryInfo extends FileInfoBase {
     subDirectoriesList() {
         return this._subDirectoriesList;
     }
+
+    isSubdirectoryOf(potentialParentDirectory: DirectoryInfo): bool {
+        if (potentialParentDirectory == null || this.path() == null || potentialParentDirectory.path() == null) {
+            return false;
+        }
+
+        var thisPath = pathUtil.resolve(this.path());
+        var potentialParentDirectoryPath = pathUtil.resolve(potentialParentDirectory.path());
+
+        return thisPath.toUpperCase().indexOf(potentialParentDirectoryPath.toUpperCase()) == 0;
+    }
 }
diff --git a/lib/FileUtils.ts b/lib/FileUtils.ts
index 4fc59be..01130ed 100644
--- a/lib/FileUtils.ts
+++ b/lib/FileUtils.ts
@@ -13,6 +13,10 @@ function kuduSync(fromPath: string, toPath: string, nextManifestPath: string, pr
         return Q.reject(new Error("From directory doesn't exist"));
     }
 
+    if (from.isSubdirectoryOf(to) || to.isSubdirectoryOf(from)) {
+        return Q.reject(new Error("Source and destination directories cannot be sub-directories of each other"));
+    }
+
     var nextManifest = new Manifest();
 
     var ignoreList = parseIgnoreList(ignore);
diff --git a/test/functionalTests.js b/test/functionalTests.js
index f9ac793..fb93b8f 100644
--- a/test/functionalTests.js
+++ b/test/functionalTests.js
@@ -137,7 +137,7 @@ suite('Kudu Sync Functional Tests', function () {
         runKuduSyncTestScenario(["file1", "file2", "file3"], [], null, done, /*whatIf*/true);
     });
 
-    test('Several files and direcotires should not be sync\'d with whatIf flag set to true', function (done) {
+    test('Several files and directories should not be sync\'d with whatIf flag set to true', function (done) {
         runKuduSyncTestScenario(["file1", "file2", "dir1/dir2/file3"], [], null, done, /*whatIf*/true);
     });
 
@@ -250,25 +250,28 @@ suite('Kudu Sync Functional Tests', function () {
     test('From directory doesn\'t exist should fail with an error', function (done) {
         var from = pathUtil.join(baseTestTempDir, testDir, 'doesntexist');
         var to = pathUtil.join(baseTestTempDir, testDir, 'to');
-        var prevManifestPath = pathUtil.join(baseTestTempDir, testDir, 'manifest');
-        var nextManifestPath = pathUtil.join(baseTestTempDir, testDir, 'manifest');
-
-        var command = testTarget.cmd + " -f " + from + " -t " + to + " -n " + nextManifestPath + " -p " + prevManifestPath;
-
-        exec(command,
-            function (error, stdout, stderr) {
-                if (stdout !== '') {
-                    console.log('---------stdout: ---------\n' + stdout);
-                }
-                if (stderr !== '') {
-                    console.log('---------stderr: ---------\n' + stderr);
-                }
-                if (error !== null) {
-                    console.log('---------exec error: ---------\n[' + error + ']');
-                }
-                should.exist(error);
-                done();
-            });
+
+        runKuduSyncTestExpectError(from, to, done);
+    });
+
+    test('KuduSync should fail when target is subdirectory of source', function (done) {
+        var from = pathUtil.join(baseTestTempDir, testDir, fromDir);
+        var to = pathUtil.join(from, 'subdirectory');
+
+        ensurePathExists(from);
+        ensurePathExists(to);
+
+        runKuduSyncTestExpectError(from, to, done);
+    });
+
+    test('KuduSync should fail when source is subdirectory of target', function (done) {
+        var to = pathUtil.join(baseTestTempDir, testDir, fromDir);
+        var from = pathUtil.join(to, 'subdirectory');
+
+        ensurePathExists(to);
+        ensurePathExists(from);
+
+        runKuduSyncTestExpectError(from, to, done);
     });
 
     setup(function () {
@@ -310,6 +313,31 @@ function runKuduSyncTestScenario(updatedFiles, expectedFiles, ignore, callback,
     });
 }
 
+function runKuduSyncTestExpectError(from, to, callback) {
+    var prevManifestPath = pathUtil.join(baseTestTempDir, testDir, 'manifest');
+    var nextManifestPath = pathUtil.join(baseTestTempDir, testDir, 'manifest');
+
+    var command = testTarget.cmd + " -f " + from + " -t " + to + " -n " + nextManifestPath + " -p " + prevManifestPath;
+    console.log("command: " + command);
+
+    var child = exec(command,
+        function (error, stdout, stderr) {
+            if (stdout !== '') {
+                console.log('---------stdout: ---------\n' + stdout);
+            }
+            if (stderr !== '') {
+                console.log('---------stderr: ---------\n' + stderr);
+            }
+            if (error !== null) {
+                console.log('---------exec error: ---------\n[' + error + ']');
+            }
+            should.exist(error);
+            callback();
+        });
+
+    child.stderr.pipe(process.stderr);
+}
+
 function removeManifestFile() {
     var manifestPath = pathUtil.join(baseTestTempDir, testDir, "manifest1");
     tryRemoveFile(manifestPath);