diff --git a/app/models/issue_relation.rb b/app/models/issue_relation.rb
index d0a66ba40..e0075cb0a 100644
--- a/app/models/issue_relation.rb
+++ b/app/models/issue_relation.rb
@@ -239,6 +239,10 @@ class IssueRelation < ActiveRecord::Base
       issue_from.blocks? issue_to
     when 'blocks'
       issue_to.blocks? issue_from
+    when 'duplicated'
+      self.class.where(issue_from_id: issue_from, issue_to_id: issue_to, relation_type: TYPE_DUPLICATES).exists?
+    when 'duplicates'
+      self.class.where(issue_from_id: issue_to, issue_to_id: issue_from, relation_type: TYPE_DUPLICATES).exists?
     when 'relates'
       self.class.where(issue_from_id: issue_to, issue_to_id: issue_from).present?
     else
diff --git a/test/unit/issue_relation_test.rb b/test/unit/issue_relation_test.rb
index 35a81ffb2..7188febab 100644
--- a/test/unit/issue_relation_test.rb
+++ b/test/unit/issue_relation_test.rb
@@ -189,6 +189,24 @@ class IssueRelationTest < ActiveSupport::TestCase
     assert_not_equal [], r.errors[:base]
   end
 
+  def test_validates_circular_dependency_on_reverse_relations_using_duplicates
+    with_locale 'en' do
+      IssueRelation.delete_all
+      issue1 = issues(:issues_001)
+      issue2 = issues(:issues_002)
+      assert IssueRelation.create!(
+              :issue_from => issue1, :issue_to => issue2,
+              :relation_type => IssueRelation::TYPE_DUPLICATES
+            )
+      r = IssueRelation.new(
+            :issue_from => issue2, :issue_to => issue1,
+            :relation_type => IssueRelation::TYPE_DUPLICATES
+          )
+      assert !r.save
+      assert_include 'This relation would create a circular dependency', r.errors.full_messages
+    end
+  end
+
   def test_create_with_initialized_journals_should_create_journals
     from = Issue.find(1)
     to   = Issue.find(2)