diff --git a/actionpack/lib/action_dispatch/middleware/cookies.rb b/actionpack/lib/action_dispatch/middleware/cookies.rb
index 0dc03a1a7e69afd9dbb9ba3f8bd86d87b5a907cd..ab7130ab08e068790265df53d4dea8251a5d925b 100644
--- a/actionpack/lib/action_dispatch/middleware/cookies.rb
+++ b/actionpack/lib/action_dispatch/middleware/cookies.rb
@@ -84,6 +84,7 @@ def []=(key, options)
 
         options[:path] ||= "/"
         @set_cookies[key] = options
+        @delete_cookies.delete(key)
         value
       end
 
diff --git a/actionpack/test/controller/cookie_test.rb b/actionpack/test/controller/cookie_test.rb
index 908967a110639053e528e9c507575e32a70411e4..36498d13a9ea5b097189ab7c580e6e4f868ef150 100644
--- a/actionpack/test/controller/cookie_test.rb
+++ b/actionpack/test/controller/cookie_test.rb
@@ -64,6 +64,12 @@ def set_permanent_signed_cookie
       cookies.permanent.signed[:remember_me] = 100
       head :ok
     end
+
+    def delete_and_set_cookie
+      cookies.delete :user_name
+      cookies[:user_name] = { :value => "david", :expires => Time.utc(2005, 10, 10,5) }
+      head :ok
+    end
   end
 
   tests TestController
@@ -152,6 +158,11 @@ def test_permanent_signed_cookie
     assert_equal 100, @controller.send(:cookies).signed[:remember_me]
   end
 
+  def test_delete_and_set_cookie
+    get :delete_and_set_cookie
+    assert_cookie_header "user_name=david; path=/; expires=Mon, 10-Oct-2005 05:00:00 GMT"
+    assert_equal({"user_name" => "david"}, @response.cookies)
+  end
 
   private
     def assert_cookie_header(expected)