diff --git a/app/controllers/commit_controller.rb b/app/controllers/commit_controller.rb
index 50556954..d671e9f9 100644
--- a/app/controllers/commit_controller.rb
+++ b/app/controllers/commit_controller.rb
@@ -26,6 +26,7 @@ class CommitController < ProjectResourceController
         end
       end
 
+      format.diff  { render text: @commit.to_diff }
       format.patch { render text: @commit.to_patch }
     end
   end
diff --git a/spec/routing/project_routing_spec.rb b/spec/routing/project_routing_spec.rb
index dc687d2a..8f2bcb2b 100644
--- a/spec/routing/project_routing_spec.rb
+++ b/spec/routing/project_routing_spec.rb
@@ -285,6 +285,7 @@ end
 describe CommitController, "routing" do
   it "to #show" do
     get("/gitlabhq/commit/4246fb").should route_to('commit#show', project_id: 'gitlabhq', id: '4246fb')
+    get("/gitlabhq/commit/4246fb.diff").should route_to('commit#show', project_id: 'gitlabhq', id: '4246fb', format: 'diff')
     get("/gitlabhq/commit/4246fb.patch").should route_to('commit#show', project_id: 'gitlabhq', id: '4246fb', format: 'patch')
     get("/gitlabhq/commit/4246fbd13872934f72a8fd0d6fb1317b47b59cb5").should route_to('commit#show', project_id: 'gitlabhq', id: '4246fbd13872934f72a8fd0d6fb1317b47b59cb5')
   end