diff --git a/lib/redmine/wiki_formatting.rb b/lib/redmine/wiki_formatting.rb
index 79da2a38..553f7713 100644
--- a/lib/redmine/wiki_formatting.rb
+++ b/lib/redmine/wiki_formatting.rb
@@ -26,7 +26,7 @@ module Redmine
     class TextileFormatter < RedCloth
       
       # auto_link rule after textile rules so that it doesn't break !image_url! tags
-      RULES = [:textile, :inline_auto_link, :inline_auto_mailto, :inline_toc, :inline_macros]
+      RULES = [:textile, :block_markdown_rule, :inline_auto_link, :inline_auto_mailto, :inline_toc, :inline_macros]
       
       def initialize(*args)
         super
diff --git a/test/unit/helpers/application_helper_test.rb b/test/unit/helpers/application_helper_test.rb
index fa210913..182cd3ae 100644
--- a/test/unit/helpers/application_helper_test.rb
+++ b/test/unit/helpers/application_helper_test.rb
@@ -160,6 +160,11 @@ class ApplicationHelperTest < HelperTestCase
     to_test.each { |text, result| assert_equal "<table>#{result}</table>", textilizable(text).gsub(/[\t\n]/, '') }
   end
   
+  def test_wiki_horizontal_rule
+    assert_equal '<hr />', textilizable('---')
+    assert_equal '<p>Dashes: ---</p>', textilizable('Dashes: ---')
+  end
+  
   def test_macro_hello_world
     text = "{{hello_world}}"
     assert textilizable(text).match(/Hello world!/)