diff --git a/lib/start-server.js b/lib/start-server.js
index de8d79d9ec..4e089833eb 100755
--- a/lib/start-server.js
+++ b/lib/start-server.js
@@ -8,22 +8,25 @@
  */
 
 require("babel-register")({
-	babelrc: false,
-	only: [__dirname, process.cwd() + "/core"],
-	plugins: [require("./server/translate-plugin.js")],
-	presets: ["react", "env"]
+  babelrc: false,
+  only: [__dirname, process.cwd() + "/core"],
+  plugins: [require("./server/translate-plugin.js")],
+  presets: ["react", "env"]
 });
 
+// For verifying port usage
+const tcpPortUsed = require('tcp-port-used');
+
 // initial check that required files are present
 const chalk = require("chalk");
 const fs = require("fs");
 const CWD = process.cwd();
 
 if (!fs.existsSync(CWD + "/siteConfig.js")) {
-	console.error(
-		chalk.red("Error: No siteConfig.js file found in website folder!")
-	);
-	process.exit(1);
+  console.error(
+    chalk.red("Error: No siteConfig.js file found in website folder!")
+  );
+  process.exit(1);
 }
 
 const program = require("commander");
@@ -32,6 +35,17 @@ program.option("--port <number>", "Specify port number").parse(process.argv);
 
 const port = program.port || 3000;
 
+console.log("Checking if port " + port + " is free...");
+tcpPortUsed.check(port, "localhost")
+.then(function(inUse) {
+  if (inUse) {
+    console.error(
+      chalk.red("Port " + port + " is in use")
+    );
+    process.exit(1);
+  }
+});
+
 // start local server on specified port
 const server = require("./server/server.js");
 server(port);
diff --git a/package.json b/package.json
index cdf8d95d14..522f072e13 100644
--- a/package.json
+++ b/package.json
@@ -20,7 +20,8 @@
     "react-dom-factories": "^1.0.1",
     "request": "^2.81.0",
     "shelljs": "^0.7.8",
-    "sitemap": "^1.13.0"
+    "sitemap": "^1.13.0",
+    "tcp-port-used": "^0.1.2"
   },
   "name": "docusaurus",
   "version": "1.0.0-beta.5",