diff --git a/lib/rbconfig/obsolete.rb b/lib/rbconfig/obsolete.rb
deleted file mode 100644
index eae9155af6..0000000000
--- a/lib/rbconfig/obsolete.rb
+++ /dev/null
@@ -1,5 +0,0 @@
-loc = caller[0]
-loc = loc[/\A.*:\d+:/] if loc
-loc = "#{loc} " if loc
-warn "#{loc}Use RbConfig instead of obsolete and deprecated Config."
-Config = RbConfig # compatibility for ruby-1.8.4 and older.
diff --git a/tool/mkconfig.rb b/tool/mkconfig.rb
index b707c4bd64..7e943f3c21 100755
--- a/tool/mkconfig.rb
+++ b/tool/mkconfig.rb
@@ -248,7 +248,6 @@ print <<EOS
     )
   end
 end
-autoload :Config, "rbconfig/obsolete.rb" # compatibility for ruby-1.8.4 and older.
 CROSS_COMPILING = nil unless defined? CROSS_COMPILING
 EOS