diff --git a/lib/oauth.js b/lib/oauth.js
index 74382b1..2721195 100644
--- a/lib/oauth.js
+++ b/lib/oauth.js
@@ -1,5 +1,6 @@
 var sha1= require('./sha1'),
-    http= require('http'); 
+    http= require('http'),
+    URL= require('url'); 
 
 exports.OAuth= function(requestUrl, accessUrl, authorizeUrl, consumerKey, consumerSecret, version, signatureMethod) {
   this._requestUrl= requestUrl;
@@ -41,6 +42,18 @@ exports.OAuth.prototype._getSignature= function(method, url, parameters, tokenSe
   return this._createSignature( signatureBase, tokenSecret ); 
 }
 
+exports.OAuth.prototype._normalizeUrl= function(url) {
+  var parsedUrl= URL.parse(url, true)
+   var port ="";
+   if( parsedUrl.port ) { 
+     if( (parsedUrl.protocol == "http:" && parsedUrl.port != "80" ) ||
+         (parsedUrl.protocol == "https:" && parsedUrl.port != "443") ) {
+           port= ":" + parsedUrl.port;
+         }
+   }
+  return parsedUrl.protocol + "//" + parsedUrl.hostname + port + parsedUrl.pathname;
+}
+
 exports.OAuth.prototype._splitQueryString= function(stringToSplit) {
   var result= {};
   var parameters= stringToSplit.split("&");
@@ -81,7 +94,7 @@ exports.OAuth.prototype._normaliseRequestParams= function(arguments) {
 }
 
 exports.OAuth.prototype._createSignatureBase= function(method, url, parameters) {
-  url= this._encodeData(url);
+  url= this._encodeData( this._normalizeUrl(url) );
   parameters= this._encodeData(parameters);
   return method.toUpperCase() + "&" + url + "&" + parameters;
 }
diff --git a/spec/spec.oauth.js b/spec/spec.oauth.js
index 96cd826..6e379a7 100644
--- a/spec/spec.oauth.js
+++ b/spec/spec.oauth.js
@@ -9,6 +9,17 @@ describe 'node-oauth'
                                             "file=vacation.jpg&oauth_consumer_key=dpf43f3p2l4k3l03&oauth_nonce=kllo9940pd9333jh&oauth_signature_method=HMAC-SHA1&oauth_timestamp=1191242096&oauth_token=nnch734d00sl2jdk&oauth_version=1.0&size=original")
         result.should.eql "GET&http%3A%2F%2Fphotos.example.net%2Fphotos&file%3Dvacation.jpg%26oauth_consumer_key%3Ddpf43f3p2l4k3l03%26oauth_nonce%3Dkllo9940pd9333jh%26oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D1191242096%26oauth_token%3Dnnch734d00sl2jdk%26oauth_version%3D1.0%26size%3Doriginal"
       end
+      describe 'Url normalisation'
+        it 'should strip default ports from urls for use in signature generation'
+          var oa= new OAuth();
+          oa._normalizeUrl("https://somehost.com:443/foo/bar").should_be "https://somehost.com/foo/bar"
+        end
+        it 'should leave in non-default ports from urls for use in signature generation'
+          var oa= new OAuth();
+          oa._normalizeUrl("https://somehost.com:446/foo/bar").should_be "https://somehost.com:446/foo/bar"
+          oa._normalizeUrl("http://somehost.com:81/foo/bar").should_be "http://somehost.com:81/foo/bar"
+        end
+      end
     end
   end
 end
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