diff --git a/index.js b/index.js
index 7836643..e43ade1 100644
--- a/index.js
+++ b/index.js
@@ -54,6 +54,13 @@ module.exports = exports = function install(opts) {
           cmd.args.push('--no-optional');
         }
 
+        if (cmd.cmd === 'bower' && opts && opts.bowerDir) {
+          cmd.cmd = path.join(opts.bowerDir, cmd.cmd);
+        }
+        if (cmd.cmd === 'npm' && opts && opts.npmDir) {
+          cmd.cmd = path.join(opts.npmDir, cmd.cmd);
+        }
+
         cmd.cwd = path.dirname(file.path);
         toRun.push(cmd);
       }
diff --git a/test/install_test.js b/test/install_test.js
index 082caa1..456b759 100644
--- a/test/install_test.js
+++ b/test/install_test.js
@@ -493,6 +493,61 @@ describe('gulp-install', function () {
 
     stream.end();
   });
+
+  it('should run `/usr/local/npm install` if stream contains `package.json` and `npmDir` option is set', function (done) {
+    var file = fixture('package.json');
+
+    var stream = install({npmDir : '/usr/local'});
+
+    stream.on('error', function(err) {
+      should.exist(err);
+      done(err);
+    });
+
+    stream.on('data', function () {
+    });
+
+    stream.on('end', function () {
+      commandRunner.run.called.should.equal(1);
+      commandRunner.run.commands[0].cmd.should.equal('/usr/local/npm');
+      commandRunner.run.commands[0].args.should.eql(['install']);
+      done();
+    });
+
+    stream.write(file);
+
+    stream.end();
+  });
+
+
+  it('should run `/usr/local/bower install --config.interactive=false` if stream contains `bower.json` and `bowerDir` option is set', function (done) {
+    var file = fixture('bower.json');
+
+    var stream = install({
+      bowerDir : '/usr/local'
+    });
+
+    stream.on('error', function(err) {
+      should.exist(err);
+      done(err);
+    });
+
+    stream.on('data', function () {
+    });
+
+    stream.on('end', function () {
+      commandRunner.run.called.should.equal(1);
+      commandRunner.run.commands[0].cmd.should.equal('/usr/local/bower');
+      commandRunner.run.commands[0].args.should.eql(['install', '--config.interactive=false']);
+      done();
+    });
+
+    stream.write(file);
+
+    stream.end();
+
+  });
+
 });
 
 function mockRunner () {