diff --git a/lib/async.js b/lib/async.js
index ed7cc7c1..762c0038 100644
--- a/lib/async.js
+++ b/lib/async.js
@@ -42,6 +42,20 @@ var maybeRealpath = function maybeRealpath(realpath, x, opts, cb) {
     }
 };
 
+var defaultReadPkg = function defaultReadPkg(readFile, pkgfile, cb) {
+    readFile(pkgfile, function (readFileErr, body) {
+        if (readFileErr) cb(readFileErr);
+        else {
+            try {
+                var pkg = JSON.parse(body);
+                cb(null, pkg);
+            } catch (jsonErr) {
+                cb(null);
+            }
+        }
+    });
+};
+
 var getPackageCandidates = function getPackageCandidates(x, start, opts) {
     var dirs = nodeModulesPaths(start, opts, x);
     for (var i = 0; i < dirs.length; i++) {
@@ -70,6 +84,7 @@ module.exports = function resolve(x, options, callback) {
     var isDirectory = opts.isDirectory || defaultIsDir;
     var readFile = opts.readFile || fs.readFile;
     var realpath = opts.realpath || defaultRealpath;
+    var readPkg = opts.readPkg || defaultReadPkg;
     var packageIterator = opts.packageIterator;
 
     var extensions = opts.extensions || ['.js'];
@@ -211,9 +226,10 @@ module.exports = function resolve(x, options, callback) {
                 // on err, ex is false
                 if (!ex) return loadpkg(path.dirname(dir), cb);
 
-                readFile(pkgfile, function (err, body) {
+                readPkg(readFile, pkgfile, function (err, pkgParam) {
                     if (err) cb(err);
-                    try { var pkg = JSON.parse(body); } catch (jsonErr) {}
+
+                    var pkg = pkgParam;
 
                     if (pkg && opts.packageFilter) {
                         pkg = opts.packageFilter(pkg, pkgfile, dir);
@@ -239,11 +255,10 @@ module.exports = function resolve(x, options, callback) {
                 if (err) return cb(err);
                 if (!ex) return loadAsFile(path.join(x, 'index'), fpkg, cb);
 
-                readFile(pkgfile, function (err, body) {
+                readPkg(readFile, pkgfile, function (err, pkgParam) {
                     if (err) return cb(err);
-                    try {
-                        var pkg = JSON.parse(body);
-                    } catch (jsonErr) {}
+
+                    var pkg = pkgParam;
 
                     if (pkg && opts.packageFilter) {
                         pkg = opts.packageFilter(pkg, pkgfile, pkgdir);
diff --git a/lib/sync.js b/lib/sync.js
index b7c5c380..b85551fe 100644
--- a/lib/sync.js
+++ b/lib/sync.js
@@ -45,6 +45,14 @@ var maybeRealpathSync = function maybeRealpathSync(realpathSync, x, opts) {
     return x;
 };
 
+var defaultReadPkgSync = function defaultReadPkgSync(readFileSync, pkgfile) {
+    var body = readFileSync(pkgfile);
+    try {
+        var pkg = JSON.parse(body);
+        return pkg;
+    } catch (jsonErr) {}
+};
+
 var getPackageCandidates = function getPackageCandidates(x, start, opts) {
     var dirs = nodeModulesPaths(start, opts, x);
     for (var i = 0; i < dirs.length; i++) {
@@ -63,6 +71,7 @@ module.exports = function resolveSync(x, options) {
     var isDirectory = opts.isDirectory || defaultIsDir;
     var readFileSync = opts.readFileSync || fs.readFileSync;
     var realpathSync = opts.realpathSync || defaultRealpathSync;
+    var readPkgSync = opts.readPkgSync || defaultReadPkgSync;
     var packageIterator = opts.packageIterator;
 
     var extensions = opts.extensions || ['.js'];
@@ -133,10 +142,8 @@ module.exports = function resolveSync(x, options) {
             return loadpkg(path.dirname(dir));
         }
 
-        var body = readFileSync(pkgfile);
-
         try {
-            var pkg = JSON.parse(body);
+            var pkg = readPkgSync(readFileSync, pkgfile);
         } catch (jsonErr) {}
 
         if (pkg && opts.packageFilter) {
@@ -150,8 +157,7 @@ module.exports = function resolveSync(x, options) {
         var pkgfile = path.join(isDirectory(x) ? maybeRealpathSync(realpathSync, x, opts) : x, '/package.json');
         if (isFile(pkgfile)) {
             try {
-                var body = readFileSync(pkgfile, 'UTF8');
-                var pkg = JSON.parse(body);
+                var pkg = readPkgSync(readFileSync, pkgfile);
             } catch (e) {}
 
             if (pkg && opts.packageFilter) {
diff --git a/readme.markdown b/readme.markdown
index 2503eb5e..1e00372f 100644
--- a/readme.markdown
+++ b/readme.markdown
@@ -71,7 +71,10 @@ options are:
 
 * opts.realpath - function to asynchronously resolve a potential symlink to its real path
 
-* opts.realpath - function to asynchronously resolve a potential symlink to its real path
+* `opts.readPkg(readFile, pkgfile, cb)` - function to asynchronously read and parse a package.json file
+  * readFile - the passed `opts.readFile` or `fs.readFile` if not specified
+  * pkgfile - path to package.json
+  * cb - callback
 
 * `opts.packageFilter(pkg, pkgfile, dir)` - transform the parsed package.json contents before looking at the "main" field
   * pkg - package data
@@ -137,6 +140,19 @@ default `opts` values:
             else cb(null, realPathErr ? file : realPath);
         });
     },
+    readPkg: function defaultReadPkg(readFile, pkgfile, cb) {
+        readFile(pkgfile, function (readFileErr, body) {
+            if (readFileErr) cb(readFileErr);
+            else {
+                try {
+                    var pkg = JSON.parse(body);
+                    cb(null, pkg);
+                } catch (jsonErr) {
+                    cb(null);
+                }
+            }
+        });
+    },
     moduleDirectory: 'node_modules',
     preserveSymlinks: false
 }
@@ -155,7 +171,7 @@ options are:
 
 * opts.includeCoreModules - set to `false` to exclude node core modules (e.g. `fs`) from the search
 
-* opts.readFile - how to read files synchronously
+* opts.readFileSync - how to read files synchronously
 
 * opts.isFile - function to synchronously test whether a file exists
 
@@ -163,6 +179,10 @@ options are:
 
 * opts.realpathSync - function to synchronously resolve a potential symlink to its real path
 
+* `opts.readPkgSync(readFileSync, pkgfile)` - function to synchronously read and parse a package.json file
+  * readFileSync - the passed `opts.readFileSync` or `fs.readFileSync` if not specified
+  * pkgfile - path to package.json
+
 * `opts.packageFilter(pkg, pkgfile, dir)` - transform the parsed package.json contents before looking at the "main" field
   * pkg - package data
   * pkgfile - path to package.json
@@ -231,6 +251,13 @@ default `opts` values:
         }
         return file;
     },
+    readPkgSync: function readPkgSync(readFileSync, pkgfile) {
+        var body = readFileSync(pkgfile);
+        try {
+            var pkg = JSON.parse(body);
+            return pkg;
+        } catch (jsonErr) {}
+    },
     moduleDirectory: 'node_modules',
     preserveSymlinks: false
 }
diff --git a/test/mock.js b/test/mock.js
index b9f17fe2..b3e17001 100644
--- a/test/mock.js
+++ b/test/mock.js
@@ -237,3 +237,49 @@ test('symlinked', function (t) {
         t.equal(pkg, undefined);
     });
 });
+
+test('readPkg', function (t) {
+    t.plan(2);
+
+    var files = {};
+    files[path.resolve('/foo/node_modules/bar/something-else.js')] = 'beep';
+    files[path.resolve('/foo/node_modules/bar/package.json')] = JSON.stringify({
+        main: './baz.js'
+    });
+
+    var dirs = {};
+    dirs[path.resolve('/foo')] = true;
+    dirs[path.resolve('/foo/node_modules')] = true;
+
+    function opts(basedir) {
+        return {
+            basedir: path.resolve(basedir),
+            isFile: function (file, cb) {
+                cb(null, Object.prototype.hasOwnProperty.call(files, path.resolve(file)));
+            },
+            isDirectory: function (dir, cb) {
+                cb(null, !!dirs[path.resolve(dir)]);
+            },
+            'package': { main: 'bar' },
+            readFile: function (file, cb) {
+                cb(null, files[path.resolve(file)]);
+            },
+            realpath: function (file, cb) {
+                cb(null, file);
+            },
+            readPkg: function (readFile, file, cb) {
+                if (file.indexOf('bar/package.json') >= 0) {
+                    cb(null, { main: './something-else.js' });
+                } else {
+                    cb(null, JSON.parse(files[path.resolve(file)]));
+                }
+            }
+        };
+    }
+
+    resolve('bar', opts('/foo'), function (err, res, pkg) {
+        if (err) return t.fail(err);
+        t.equal(res, path.resolve('/foo/node_modules/bar/something-else.js'));
+        t.equal(pkg && pkg.main, './something-else.js');
+    });
+});
diff --git a/test/mock_sync.js b/test/mock_sync.js
index ef2bc6d3..46a98883 100644
--- a/test/mock_sync.js
+++ b/test/mock_sync.js
@@ -140,3 +140,48 @@ test('symlinked', function (t) {
         path.resolve('/foo/bar/symlinked/baz.js')
     );
 });
+
+test('readPkgSync', function (t) {
+    t.plan(1);
+
+    var files = {};
+    files[path.resolve('/foo/node_modules/bar/something-else.js')] = 'beep';
+    files[path.resolve('/foo/node_modules/bar/package.json')] = JSON.stringify({
+        main: './baz.js'
+    });
+
+    var dirs = {};
+    dirs[path.resolve('/foo')] = true;
+    dirs[path.resolve('/foo/node_modules')] = true;
+
+    function opts(basedir) {
+        return {
+            basedir: path.resolve(basedir),
+            isFile: function (file) {
+                return Object.prototype.hasOwnProperty.call(files, path.resolve(file));
+            },
+            isDirectory: function (dir) {
+                return !!dirs[path.resolve(dir)];
+            },
+            readFileSync: function (file) {
+                return files[path.resolve(file)];
+            },
+            realpathSync: function (file) {
+                return file;
+            },
+            readPkgSync: function (readFileSync, file) {
+                if (file.indexOf('bar/package.json') >= 0) {
+                    return { main: './something-else.js' };
+                } else {
+                    return JSON.parse(files[path.resolve(file)]);
+                }
+            }
+        };
+    }
+
+    t.equal(
+        resolve.sync('bar', opts('/foo')),
+        path.resolve('/foo/node_modules/bar/something-else.js')
+    );
+});
+