diff --git a/README b/README.rdoc
similarity index 100%
rename from README
rename to README.rdoc
diff --git a/Rakefile b/Rakefile
index e608af0319..c49942c0bb 100644
--- a/Rakefile
+++ b/Rakefile
@@ -69,7 +69,7 @@ Rake::RDocTask.new do |rdoc|
   rdoc.options << '--line-numbers' << '--inline-source'
   rdoc.options << '-A cattr_accessor=object'
   rdoc.options << '--charset' << 'utf-8'
-  rdoc.options << '--main' << 'railties/README'
+  rdoc.options << '--main' << 'README.rdoc'
 
   # Workaround: RDoc assumes that rdoc.template can be required, and that
   # rdoc.template.upcase is a constant living in RDoc::Generator::HTML
@@ -83,38 +83,38 @@ Rake::RDocTask.new do |rdoc|
 
   rdoc.rdoc_files.include('railties/CHANGELOG')
   rdoc.rdoc_files.include('railties/MIT-LICENSE')
-  rdoc.rdoc_files.include('railties/README')
+  rdoc.rdoc_files.include('railties/README.rdoc')
   rdoc.rdoc_files.include('railties/lib/**/*.rb')
   rdoc.rdoc_files.exclude('railties/lib/rails/generators/**/templates/*')
 
-  rdoc.rdoc_files.include('activerecord/README')
+  rdoc.rdoc_files.include('activerecord/README.rdoc')
   rdoc.rdoc_files.include('activerecord/CHANGELOG')
   rdoc.rdoc_files.include('activerecord/lib/active_record/**/*.rb')
   rdoc.rdoc_files.exclude('activerecord/lib/active_record/vendor/*')
 
-  rdoc.rdoc_files.include('activeresource/README')
+  rdoc.rdoc_files.include('activeresource/README.rdoc')
   rdoc.rdoc_files.include('activeresource/CHANGELOG')
   rdoc.rdoc_files.include('activeresource/lib/active_resource.rb')
   rdoc.rdoc_files.include('activeresource/lib/active_resource/*')
 
-  rdoc.rdoc_files.include('actionpack/README')
+  rdoc.rdoc_files.include('actionpack/README.rdoc')
   rdoc.rdoc_files.include('actionpack/CHANGELOG')
   rdoc.rdoc_files.include('actionpack/lib/action_controller/**/*.rb')
   rdoc.rdoc_files.include('actionpack/lib/action_dispatch/**/*.rb')
   rdoc.rdoc_files.include('actionpack/lib/action_view/**/*.rb')
   rdoc.rdoc_files.exclude('actionpack/lib/action_controller/vendor/*')
 
-  rdoc.rdoc_files.include('actionmailer/README')
+  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.exclude('actionmailer/lib/action_mailer/vendor/*')
 
-  rdoc.rdoc_files.include('activesupport/README')
+  rdoc.rdoc_files.include('activesupport/README.rdoc')
   rdoc.rdoc_files.include('activesupport/CHANGELOG')
   rdoc.rdoc_files.include('activesupport/lib/active_support/**/*.rb')
   rdoc.rdoc_files.exclude('activesupport/lib/active_support/vendor/*')
 
-  rdoc.rdoc_files.include('activemodel/README')
+  rdoc.rdoc_files.include('activemodel/README.rdoc')
   rdoc.rdoc_files.include('activemodel/CHANGELOG')
   rdoc.rdoc_files.include('activemodel/lib/active_model/**/*.rb')
 end
diff --git a/actionmailer/README b/actionmailer/README.rdoc
similarity index 100%
rename from actionmailer/README
rename to actionmailer/README.rdoc
diff --git a/actionmailer/Rakefile b/actionmailer/Rakefile
index f20e7ea928..98aeae9818 100644
--- a/actionmailer/Rakefile
+++ b/actionmailer/Rakefile
@@ -32,7 +32,7 @@ Rake::RDocTask.new { |rdoc|
   rdoc.options << '--line-numbers' << '--inline-source' << '-A cattr_accessor=object'
   rdoc.options << '--charset' << 'utf-8'
   rdoc.template = ENV['template'] ? "#{ENV['template']}.rb" : '../doc/template/horo'
-  rdoc.rdoc_files.include('README', 'CHANGELOG')
+  rdoc.rdoc_files.include('README.rdoc', 'CHANGELOG')
   rdoc.rdoc_files.include('lib/action_mailer.rb')
   rdoc.rdoc_files.include('lib/action_mailer/*.rb')
   rdoc.rdoc_files.include('lib/action_mailer/delivery_method/*.rb')
diff --git a/actionpack/README b/actionpack/README.rdoc
similarity index 100%
rename from actionpack/README
rename to actionpack/README.rdoc
diff --git a/actionpack/Rakefile b/actionpack/Rakefile
index aed5278e38..3a988d832d 100644
--- a/actionpack/Rakefile
+++ b/actionpack/Rakefile
@@ -47,7 +47,7 @@ Rake::RDocTask.new { |rdoc|
   if ENV['DOC_FILES']
     rdoc.rdoc_files.include(ENV['DOC_FILES'].split(/,\s*/))
   else
-    rdoc.rdoc_files.include('README', 'RUNNING_UNIT_TESTS', 'CHANGELOG')
+    rdoc.rdoc_files.include('README.rdoc', 'RUNNING_UNIT_TESTS', 'CHANGELOG')
     rdoc.rdoc_files.include(Dir['lib/**/*.rb'] -
                             Dir['lib/*/vendor/**/*.rb'])
     rdoc.rdoc_files.exclude('lib/actionpack.rb')
diff --git a/activemodel/README b/activemodel/README.rdoc
similarity index 100%
rename from activemodel/README
rename to activemodel/README.rdoc
diff --git a/activemodel/Rakefile b/activemodel/Rakefile
index 1dba664539..4e4bbcee96 100644
--- a/activemodel/Rakefile
+++ b/activemodel/Rakefile
@@ -32,7 +32,7 @@ Rake::RDocTask.new do |rdoc|
   rdoc.options << '--line-numbers' << '--inline-source' << '-A cattr_accessor=object'
   rdoc.options << '--charset' << 'utf-8'
   rdoc.template = ENV['template'] ? "#{ENV['template']}.rb" : '../doc/template/horo'
-  rdoc.rdoc_files.include("README", "CHANGELOG")
+  rdoc.rdoc_files.include("README.rdoc", "CHANGELOG")
   rdoc.rdoc_files.include("lib/**/*.rb")
 end
 
diff --git a/activerecord/README b/activerecord/README.rdoc
similarity index 100%
rename from activerecord/README
rename to activerecord/README.rdoc
diff --git a/activerecord/Rakefile b/activerecord/Rakefile
index 392b717e0a..d9124c9776 100644
--- a/activerecord/Rakefile
+++ b/activerecord/Rakefile
@@ -172,7 +172,7 @@ Rake::RDocTask.new { |rdoc|
   rdoc.options << '--line-numbers' << '--inline-source' << '-A cattr_accessor=object'
   rdoc.options << '--charset' << 'utf-8'
   rdoc.template = ENV['template'] ? "#{ENV['template']}.rb" : '../doc/template/horo'
-  rdoc.rdoc_files.include('README', 'RUNNING_UNIT_TESTS', 'CHANGELOG')
+  rdoc.rdoc_files.include('README.rdoc', 'RUNNING_UNIT_TESTS', 'CHANGELOG')
   rdoc.rdoc_files.include('lib/**/*.rb')
   rdoc.rdoc_files.exclude('lib/active_record/vendor/*')
   rdoc.rdoc_files.include('dev-utils/*.rb')
diff --git a/activeresource/README b/activeresource/README.rdoc
similarity index 100%
rename from activeresource/README
rename to activeresource/README.rdoc
diff --git a/activeresource/Rakefile b/activeresource/Rakefile
index 04b08ed8cb..b1e5ca91d3 100644
--- a/activeresource/Rakefile
+++ b/activeresource/Rakefile
@@ -35,7 +35,7 @@ Rake::RDocTask.new { |rdoc|
   rdoc.options << '--line-numbers' << '--inline-source' << '-A cattr_accessor=object'
   rdoc.options << '--charset' << 'utf-8'
   rdoc.template = ENV['template'] ? "#{ENV['template']}.rb" : '../doc/template/horo'
-  rdoc.rdoc_files.include('README', 'CHANGELOG')
+  rdoc.rdoc_files.include('README.rdoc', 'CHANGELOG')
   rdoc.rdoc_files.include('lib/**/*.rb')
   rdoc.rdoc_files.exclude('lib/activeresource.rb')
 }
diff --git a/activesupport/README b/activesupport/README.rdoc
similarity index 100%
rename from activesupport/README
rename to activesupport/README.rdoc
diff --git a/activesupport/Rakefile b/activesupport/Rakefile
index 2aebe05de2..77b1a8431d 100644
--- a/activesupport/Rakefile
+++ b/activesupport/Rakefile
@@ -28,7 +28,7 @@ Rake::RDocTask.new { |rdoc|
   rdoc.options << '--line-numbers' << '--inline-source'
   rdoc.options << '--charset' << 'utf-8'
   rdoc.template = ENV['template'] ? "#{ENV['template']}.rb" : '../doc/template/horo'
-  rdoc.rdoc_files.include('README', 'CHANGELOG')
+  rdoc.rdoc_files.include('README.rdoc', 'CHANGELOG')
   rdoc.rdoc_files.include('lib/active_support.rb')
   rdoc.rdoc_files.include('lib/active_support/**/*.rb')
 }
diff --git a/railties/README b/railties/README.rdoc
similarity index 100%
rename from railties/README
rename to railties/README.rdoc
diff --git a/railties/Rakefile b/railties/Rakefile
index ae9db3c022..19c860f257 100644
--- a/railties/Rakefile
+++ b/railties/Rakefile
@@ -59,7 +59,7 @@ Rake::RDocTask.new { |rdoc|
   rdoc.options << '--line-numbers' << '--inline-source' << '--accessor' << 'cattr_accessor=object'
   rdoc.options << '--charset' << 'utf-8'
   rdoc.template = ENV['template'] ? "#{ENV['template']}.rb" : '../doc/template/horo'
-  rdoc.rdoc_files.include('README', 'CHANGELOG')
+  rdoc.rdoc_files.include('README.rdoc', 'CHANGELOG')
   rdoc.rdoc_files.include('lib/**/*.rb')
   rdoc.rdoc_files.exclude('lib/rails/generators/**/templates/*')
 }