diff --git a/Rakefile b/Rakefile
index 53acd077d7b9ae78daee3cf21be57ca8bf2680bd..607ce01fd0de113ca0dbd5efba9b0384152bcebe 100755
--- a/Rakefile
+++ b/Rakefile
@@ -85,6 +85,7 @@ RDoc::Task.new do |rdoc|
   rdoc.rdoc_files.include('actionmailer/README.rdoc')
   rdoc.rdoc_files.include('actionmailer/CHANGELOG')
   rdoc.rdoc_files.include('actionmailer/lib/action_mailer/base.rb')
+  rdoc.rdoc_files.include('actionmailer/lib/action_mailer/mail_helper.rb')
   rdoc.rdoc_files.exclude('actionmailer/lib/action_mailer/vendor/*')
 
   rdoc.rdoc_files.include('activesupport/README.rdoc')