diff --git a/packages/angular-cli/commands/serve.ts b/packages/angular-cli/commands/serve.ts
index 936a341b4cfc..c30e5520f222 100644
--- a/packages/angular-cli/commands/serve.ts
+++ b/packages/angular-cli/commands/serve.ts
@@ -26,6 +26,7 @@ export interface ServeTaskOptions {
   sslKey?: string;
   sslCert?: string;
   aot?: boolean;
+  open?: boolean;
 }
 
 const ServeCommand = Command.extend({
@@ -79,7 +80,14 @@ const ServeCommand = Command.extend({
     { name: 'ssl',                  type: Boolean, default: false },
     { name: 'ssl-key',              type: String,  default: 'ssl/server.key' },
     { name: 'ssl-cert',             type: String,  default: 'ssl/server.crt' },
-    { name: 'aot',                  type: Boolean, default: false }
+    { name: 'aot',                  type: Boolean, default: false },
+    {
+      name: 'open',
+      type: Boolean,
+      default: false,
+      aliases: ['o'],
+      description: 'Opens the url in default browser',
+    },
   ],
 
   run: function(commandOptions: ServeTaskOptions) {
diff --git a/packages/angular-cli/tasks/serve-webpack.ts b/packages/angular-cli/tasks/serve-webpack.ts
index f09e21de0dca..42d16c9c4712 100644
--- a/packages/angular-cli/tasks/serve-webpack.ts
+++ b/packages/angular-cli/tasks/serve-webpack.ts
@@ -11,6 +11,8 @@ import { NgCliWebpackConfig } from '../models/webpack-config';
 import { ServeTaskOptions } from '../commands/serve';
 import { CliConfig } from '../models/config';
 import { oneLine } from 'common-tags';
+import * as url from 'url';
+const opn = require('opn');
 
 export default Task.extend({
   run: function(commandOptions: ServeTaskOptions) {
@@ -78,6 +80,11 @@ export default Task.extend({
           console.error(err.stack || err);
           if (err.details) { console.error(err.details); }
           reject(err.details);
+        } else {
+          const { open, host, port } = commandOptions;
+          if (open) {
+            opn(url.format({ protocol: 'http', hostname: host, port: port.toString() }));
+          }
         }
       });
     });
diff --git a/packages/angular-cli/utilities/completion.sh b/packages/angular-cli/utilities/completion.sh
index 907d724eaea4..250308ad371b 100644
--- a/packages/angular-cli/utilities/completion.sh
+++ b/packages/angular-cli/utilities/completion.sh
@@ -13,7 +13,7 @@ github_pages_deploy_opts='--base-href --environment --gh-token --gh-username --m
 help_opts='--json --verbose -v'
 init_opts='--dry-run inline-style inline-template --link-cli --mobile --name --prefix --routing --skip-bower --skip-npm --source-dir --style --verbose -d -is -it -lc -n -p -sb -sd -sn -v'
 new_opts='--directory --dry-run inline-style inline-template --link-cli --mobile --prefix --routing --skip-bower --skip-git --skip-npm --source-dir --style --verbose -d -dir -is -it -lc -p -sb -sd -sg -sn -v'
-serve_opts='--aot --environment --host --live-reload --live-reload-base-url --live-reload-host --live-reload-live-css --live-reload-port --port --proxy-config --ssl --ssl-cert --ssl-key --target --watcher -H -e -lr -lrbu -lrh -lrp -p -pc -t -w'
+serve_opts='--aot --environment --host --live-reload --live-reload-base-url --live-reload-host --live-reload-live-css --live-reload-port --open --port --proxy-config --ssl --ssl-cert --ssl-key --target --watcher -H -e -lr -lrbu -lrh -lrp -o -p -pc -t -w'
 set_opts='--global -g'
 test_opts='--browsers --build --colors --log-level --port --reporters --watch -w'
 version_opts='--verbose'