diff --git a/app/assets/stylesheets/generic/issue_box.scss b/app/assets/stylesheets/generic/issue_box.scss
index 94149594e24..79fbad4b946 100644
--- a/app/assets/stylesheets/generic/issue_box.scss
+++ b/app/assets/stylesheets/generic/issue_box.scss
@@ -113,6 +113,11 @@
     padding: 10px 15px;
   }
 
+  .cross-project-ref {
+    float: left;
+    padding: 10px 15px;
+  }
+
   .creator {
     float: right;
     padding: 10px 15px;
diff --git a/app/helpers/gitlab_markdown_helper.rb b/app/helpers/gitlab_markdown_helper.rb
index 7d3cb749829..800cacdc2c2 100644
--- a/app/helpers/gitlab_markdown_helper.rb
+++ b/app/helpers/gitlab_markdown_helper.rb
@@ -254,4 +254,16 @@ module GitlabMarkdownHelper
       truncated
     end
   end
+
+  def cross_project_reference(project, entity)
+    path = project.path_with_namespace
+
+    if entity.kind_of?(Issue)
+      [path, entity.iid].join('#')
+    elsif entity.kind_of?(MergeRequest)
+      [path, entity.iid].join('!')
+    else
+      raise 'Not supported type'
+    end
+  end
 end
diff --git a/app/views/projects/issues/show.html.haml b/app/views/projects/issues/show.html.haml
index aad58e48f6c..685d9f96d51 100644
--- a/app/views/projects/issues/show.html.haml
+++ b/app/views/projects/issues/show.html.haml
@@ -38,6 +38,9 @@
       - else
         Open
 
+    .cross-project-ref
+      = cross_project_reference(@project, @issue)
+
     .creator
       Created by #{link_to_member(@project, @issue.author)} #{issue_timestamp(@issue)}