diff --git a/app/controllers/projects/merge_requests_controller.rb b/app/controllers/projects/merge_requests_controller.rb
index aa8645ba8cc9dee262e0a7569ed1efd269a0550c..0288ee8771711035c84fef09368fb0a6006dcacd 100644
--- a/app/controllers/projects/merge_requests_controller.rb
+++ b/app/controllers/projects/merge_requests_controller.rb
@@ -428,6 +428,10 @@ class Projects::MergeRequestsController < Projects::ApplicationController
   end
 
   def validates_merge_request
+    # If source project was removed and merge request for some reason
+    # wasn't close (Ex. mr from fork to origin)
+    return invalid_mr if !@merge_request.source_project && @merge_request.open?
+
     # Show git not found page
     # if there is no saved commits between source & target branch
     if @merge_request.commits.blank?