diff --git a/lib/oauth2.js b/lib/oauth2.js
index a3b8617d..bdaae29b 100644
--- a/lib/oauth2.js
+++ b/lib/oauth2.js
@@ -109,7 +109,8 @@ exports.OAuth2.prototype.getOAuthAccessToken= function(code, params, callback) {
   params['client_id'] = this._clientId;
   params['client_secret'] = this._clientSecret;
   params['type']= 'web_server';
-  params['code']= code;
+  var codeParam = (params.grant_type === 'refresh_token') ? 'refresh_token' : 'code';
+  params[codeParam]= code;
 
   var post_data= querystring.stringify( params );
   var post_headers= {