diff --git a/lib/salesforce-oauth2.js b/lib/salesforce-oauth2.js
index 5d1161b..f24f8b4 100644
--- a/lib/salesforce-oauth2.js
+++ b/lib/salesforce-oauth2.js
@@ -22,7 +22,7 @@ var oauth2 = module.exports = function (options, callback) {
     var base_url = options.base_url || baseUrl;
     options = _.omit(options, "base_url");
 
-    var uri = baseUrl + tokenUrl + "?" + qs.stringify(options);
+    var uri = base_url + tokenUrl + "?" + qs.stringify(options);
 
     return request.post({
         url: uri,
diff --git a/package.json b/package.json
index 4963060..319f835 100644
--- a/package.json
+++ b/package.json
@@ -14,7 +14,7 @@
     "url": "https://github.com/cangencer/salesforce-oauth2"
   },
   "main": "lib/salesforce-oauth2",
-  "version": "0.1.7",
+  "version": "0.1.8",
   "dependencies": {
     "request": "~2.37.0",
     "underscore": "~1.6.0"
diff --git a/test/tests.js b/test/tests.js
index 520b351..64ce8ef 100644
--- a/test/tests.js
+++ b/test/tests.js
@@ -92,6 +92,21 @@ describe("tokens", function () {
                 done();
             });
         });
+       
+        it("should accept a custom authentication URL", function(done) {
+             options.base_url = "https://custom-login.salesforce.com";
+             var login = nock(options.base_url)
+                .post(expectedPath)
+                .reply(200, mockResponse);
+                                    
+            oauth2.authenticate(options, function (error, payload) {
+                should.not.exist(error);
+                payload.should.eql(mockResponse);
+                login.done();
+                done();
+            });
+
+        });
     });
 
     describe("when authenticating with an authorization code", function() {