diff --git a/bin/jest.js b/bin/jest.js
index b72cd1f5b633..428d3f106b40 100755
--- a/bin/jest.js
+++ b/bin/jest.js
@@ -18,6 +18,15 @@ var Q = require('q');
 var TestRunner = require('../src/TestRunner');
 var utils = require('../src/lib/utils');
 
+var _jestVersion = null;
+function _getJestVersion() {
+  if (_jestVersion === null) {
+    var pkgJsonPath = path.resolve(__dirname, '..', 'package.json');
+    _jestVersion = require(pkgJsonPath).version;
+  }
+  return _jestVersion;
+}
+
 function _findChangedFiles(dirPath) {
   var deferred = Q.defer();
 
@@ -102,166 +111,251 @@ function _wrapDesc(desc) {
   }, ['']).join(indent);
 }
 
-var argv = optimist
-  .usage('Usage: $0 [--config=<pathToConfigFile>] [TestPathRegExp]')
-  .options({
-    config: {
-      alias: 'c',
-      description: _wrapDesc(
-        'The path to a jest config file specifying how to find and execute ' +
-        'tests.'
-      ),
-      type: 'string'
-    },
-    coverage: {
-      description: _wrapDesc(
-        'Indicates that test coverage information should be collected and ' +
-        'reported in the output.'
-      ),
-      type: 'boolean'
-    },
-    maxWorkers: {
-      alias: 'w',
-      description: _wrapDesc(
-        'Specifies the maximum number of workers the worker-pool will spawn ' +
-        'for running tests. This defaults to the number of the cores ' +
-        'available on your machine. (its usually best not to override this ' +
-        'default)'
-      ),
-      type: 'string' // no, optimist -- its a number.. :(
-    },
-    onlyChanged: {
-      alias: 'o',
-      description: _wrapDesc(
-        'Attempts to identify which tests to run based on which files have ' +
-        'changed in the current repository. Only works if you\'re running ' +
-        'tests in a git repository at the moment.'
-      ),
-      type: 'boolean'
-    },
-    runInBand: {
-      alias: 'i',
-      description: _wrapDesc(
-        'Run all tests serially in the current process (rather than creating ' +
-        'a worker pool of child processes that run tests). This is sometimes ' +
-        'useful for debugging, but such use cases are pretty rare.'
-      ),
-      type: 'boolean'
-    }
-  })
-  .check(function(argv) {
-    if (argv.runInBand && argv.hasOwnProperty('maxWorkers')) {
-      throw (
-        "Both --runInBand and --maxWorkers were specified, but these two " +
-        "options don't make sense together. Which is it?"
-      );
-    }
+function runCLI(argv, packageRoot) {
+  if (argv.version) {
+    console.log('v' + _getJestVersion());
+    process.exit(0);
+  }
 
-    if (argv.onlyChanged && argv._.length > 0) {
-      throw (
-        "Both --onlyChanged and a path pattern were specified, but these two " +
-        "options don't make sense together. Which is it? Do you want to run " +
-        "tests for changed files? Or for a specific set of files?"
-      );
+  var config;
+  if (argv.config) {
+    config = utils.loadConfigFromFile(argv.config);
+  } else {
+    var pkgJsonPath = path.join(packageRoot, 'package.json');
+    var pkgJson = fs.existsSync(pkgJsonPath) ? require(pkgJsonPath) : {};
+
+    // First look to see if there is a package.json file with a jest config in it
+    if (pkgJson.jest) {
+      if (!pkgJson.jest.hasOwnProperty('rootDir')) {
+        pkgJson.jest.rootDir = packageRoot;
+      } else {
+        pkgJson.jest.rootDir = path.resolve(packageRoot, pkgJson.jest.rootDir);
+      }
+      config = utils.normalizeConfig(pkgJson.jest);
+      config.name = pkgJson.name;
+      config = Q(config);
+
+    // If not, use a sane default config
+    } else {
+      config = Q(utils.normalizeConfig({
+        name: packageRoot.replace(/[/\\]/g, '_'),
+        rootDir: packageRoot,
+        testPathDirs: [packageRoot],
+        testPathIgnorePatterns: ['/node_modules/.+']
+      }));
     }
-  })
-  .argv
+  }
 
-if (argv.help) {
-  optimist.showHelp();
-  process.exit();
-}
+  config.done(function(config) {
+    var pathPattern =
+      argv._.length === 0
+      ? /.*/
+      : new RegExp(argv._.join('|'));
 
-var config;
-if (argv.config) {
-  config = utils.loadConfigFromFile(argv.config);
-} else {
-  var cwd = process.cwd();
+    var testRunnerOpts = {};
+    if (argv.maxWorkers) {
+      testRunnerOpts.maxWorkers = argv.maxWorkers;
+    }
 
-  var pkgJsonPath = path.join(cwd, 'package.json');
-  var pkgJson = fs.existsSync(pkgJsonPath) ? require(pkgJsonPath) : {};
+    if (argv.coverage) {
+      config.collectCoverage = true;
+    }
 
-  // First look to see if there is a package.json file with a jest config in it
-  if (pkgJson.jest) {
-    if (!pkgJson.jest.hasOwnProperty('rootDir')) {
-      pkgJson.jest.rootDir = cwd;
+    var testRunner = new TestRunner(config, testRunnerOpts);
+
+    function _runTestsOnPathPattern(pathPattern) {
+      return testRunner.findTestPathsMatching(pathPattern)
+        .then(function(matchingTestPaths) {
+          console.log('Found ' + matchingTestPaths.length + ' matching tests...');
+          if (argv.runInBand) {
+            return testRunner.runTestsInBand(matchingTestPaths, _onResultReady);
+          } else {
+            return testRunner.runTestsParallel(matchingTestPaths, _onResultReady);
+          }
+        })
+        .then(_onRunComplete);
     }
-    config = utils.normalizeConfig(pkgJson.jest);
-    config.name = pkgJson.name;
-    config = Q(config);
 
-  // If not, use a sane default config
-  } else {
-    config = Q(utils.normalizeConfig({
-      name: cwd.replace(/[/\\]/g, '_'),
-      rootDir: cwd,
-      testPathDirs: [cwd],
-      testPathIgnorePatterns: ['/node_modules/.+']
-    }, cwd));
-  }
+    if (argv.onlyChanged) {
+      console.log('Looking for changed files...');
+
+      var testPathDirsAreGit = config.testPathDirs.map(_verifyIsGitRepository);
+      Q.all(testPathDirsAreGit).then(function(results) {
+        if (!results.every(function(result) { return result; })) {
+          console.error(
+            'It appears that one of your testPathDirs does not exist ' +
+            'with in a git repository. Currently --onlyChanged only works ' +
+            'with git projects.\n'
+          );
+          process.exit(1);
+        }
+
+        return Q.all(config.testPathDirs.map(_findChangedFiles));
+      }).then(function(changedPathSets) {
+        // Collapse changed files from each of the testPathDirs into a single list
+        // of changed file paths
+        var changedPaths = [];
+        changedPathSets.forEach(function(pathSet) {
+          changedPaths = changedPaths.concat(pathSet);
+        });
+        return testRunner.findTestsRelatedTo(changedPaths);
+      }).done(function(affectedTestPaths) {
+        if (affectedTestPaths.length > 0) {
+          _runTestsOnPathPattern(new RegExp(affectedTestPaths.join('|'))).done();
+        } else {
+          console.log('No tests to run!');
+        }
+      });
+    } else {
+      _runTestsOnPathPattern(pathPattern).done();
+    }
+  });
 }
 
-config.done(function(config) {
-  var pathPattern =
-    argv._.length === 0
-    ? /.*/
-    : new RegExp(argv._.join('|'));
+function _main() {
+  var argv = optimist
+    .usage('Usage: $0 [--config=<pathToConfigFile>] [TestPathRegExp]')
+    .options({
+      config: {
+        alias: 'c',
+        description: _wrapDesc(
+          'The path to a jest config file specifying how to find and execute ' +
+          'tests.'
+        ),
+        type: 'string'
+      },
+      coverage: {
+        description: _wrapDesc(
+          'Indicates that test coverage information should be collected and ' +
+          'reported in the output.'
+        ),
+        type: 'boolean'
+      },
+      maxWorkers: {
+        alias: 'w',
+        description: _wrapDesc(
+          'Specifies the maximum number of workers the worker-pool will spawn ' +
+          'for running tests. This defaults to the number of the cores ' +
+          'available on your machine. (its usually best not to override this ' +
+          'default)'
+        ),
+        type: 'string' // no, optimist -- its a number.. :(
+      },
+      onlyChanged: {
+        alias: 'o',
+        description: _wrapDesc(
+          'Attempts to identify which tests to run based on which files have ' +
+          'changed in the current repository. Only works if you\'re running ' +
+          'tests in a git repository at the moment.'
+        ),
+        type: 'boolean'
+      },
+      runInBand: {
+        alias: 'i',
+        description: _wrapDesc(
+          'Run all tests serially in the current process (rather than creating ' +
+          'a worker pool of child processes that run tests). This is sometimes ' +
+          'useful for debugging, but such use cases are pretty rare.'
+        ),
+        type: 'boolean'
+      },
+      version: {
+        alias: 'v',
+        description: _wrapDesc('Print the version and exit'),
+        type: 'boolean'
+      }
+    })
+    .check(function(argv) {
+      if (argv.runInBand && argv.hasOwnProperty('maxWorkers')) {
+        throw (
+          "Both --runInBand and --maxWorkers were specified, but these two " +
+          "options don't make sense together. Which is it?"
+        );
+      }
 
-  var testRunnerOpts = {};
-  if (argv.maxWorkers) {
-    testRunnerOpts.maxWorkers = argv.maxWorkers;
-  }
+      if (argv.onlyChanged && argv._.length > 0) {
+        throw (
+          "Both --onlyChanged and a path pattern were specified, but these two " +
+          "options don't make sense together. Which is it? Do you want to run " +
+          "tests for changed files? Or for a specific set of files?"
+        );
+      }
+    })
+    .argv
 
-  if (argv.coverage) {
-    config.collectCoverage = true;
+  if (argv.help) {
+    optimist.showHelp();
+    process.exit(0);
   }
 
-  var testRunner = new TestRunner(config, testRunnerOpts);
+  var cwd = process.cwd();
 
-  function _runTestsOnPathPattern(pathPattern) {
-    return testRunner.findTestPathsMatching(pathPattern)
-      .then(function(matchingTestPaths) {
-        console.log('Found ' + matchingTestPaths.length + ' matching tests...');
-        if (argv.runInBand) {
-          return testRunner.runTestsInBand(matchingTestPaths, _onResultReady);
-        } else {
-          return testRunner.runTestsParallel(matchingTestPaths, _onResultReady);
-        }
-      })
-      .then(_onRunComplete);
+  // Is the cwd somewhere within an npm package?
+  var cwdPackageRoot = cwd;
+  while (!fs.existsSync(path.join(cwdPackageRoot, 'package.json'))) {
+    if (cwdPackageRoot === '/') {
+      cwdPackageRoot = cwd;
+      break;
+    }
+    cwdPackageRoot = path.resolve(cwdPackageRoot, '..');
   }
 
-  if (argv.onlyChanged) {
-    console.log('Looking for changed files...');
+  // Is there a version of Jest installed at our cwdPackageRoot?
+  var cwdJestBinPath = path.join(
+    cwdPackageRoot,
+    'node_modules',
+    '.bin',
+    'jest'
+  );
+
+  // Is there a package.json at our cwdPackageRoot that indicates that there
+  // should be a version of Jest installed?
+  var cwdPkgJsonPath = path.join(cwdPackageRoot, 'package.json');
+
+  // If a version of Jest was found installed in the CWD package, run using that
+  if (fs.existsSync(cwdJestBinPath)) {
+    var jestBinary = require(cwdJestBinPath);
+    if (!jestBinary.runCLI) {
+      console.error(
+        'This project requires an older version of Jest than what you have ' +
+        'installed globally.\n' +
+        'Please upgrade this project past Jest version 0.1.5'
+      );
+      process.exit(1);
+    }
 
-    var testPathDirsAreGit = config.testPathDirs.map(_verifyIsGitRepository);
-    Q.all(testPathDirsAreGit).then(function(results) {
-      if (!results.every(function(result) { return result; })) {
-        console.error(
-          'It appears that one of your testPathDirs does not exist ' +
-          'with in a git repository. Currently --onlyChanged only works ' +
-          'with git projects.\n'
-        );
-        process.exit(1);
-      }
+    jestBinary.runCLI(argv, cwdPackageRoot);
+    return;
+  }
 
-      return Q.all(config.testPathDirs.map(_findChangedFiles));
-    }).then(function(changedPathSets) {
-      // Collapse changed files from each of the testPathDirs into a single list
-      // of changed file paths
-      var changedPaths = [];
-      changedPathSets.forEach(function(pathSet) {
-        changedPaths = changedPaths.concat(pathSet);
-      });
-      return testRunner.findTestsRelatedTo(changedPaths);
-    }).done(function(affectedTestPaths) {
-      if (affectedTestPaths.length > 0) {
-        _runTestsOnPathPattern(new RegExp(affectedTestPaths.join('|'))).done();
-      } else {
-        console.log('No tests to run!');
-      }
-    });
-  } else {
-    _runTestsOnPathPattern(pathPattern).done();
+  // If a package.json was found in the CWD package indicating a specific
+  // version of Jest to be used, bail out and ask the user to `npm install`
+  // first
+  if (fs.existsSync(cwdPkgJsonPath)) {
+    var cwdPkgJson = require(cwdPkgJsonPath);
+    var cwdPkgDeps = cwdPkgJson.dependencies;
+    var cwdPkgDevDeps = cwdPkgJson.devDependencies;
+
+    var thisJestVersion = _getJestVersion();
+
+    if (cwdPkgDeps && cwdPkgDeps['jest-cli']
+        || cwdPkgDevDeps && cwdPkgDevDeps['jest-cli']) {
+      console.error(
+        'Please run `npm install` to use the version of Jest intended for ' +
+        'this project.'
+      );
+      process.exit(1);
+    }
+  }
+
+  if (!argv.version && cwdPackageRoot) {
+    console.log('Using Jest CLI v' + _getJestVersion());
   }
-});
+  runCLI(argv, cwdPackageRoot);
+}
+
+exports.runCLI = runCLI;
+
+if (require.main === module) {
+  _main();
+}