diff --git a/Library/Homebrew/os/mac.rb b/Library/Homebrew/os/mac.rb
index 654f2d5c04..f559bfacf9 100644
--- a/Library/Homebrew/os/mac.rb
+++ b/Library/Homebrew/os/mac.rb
@@ -21,7 +21,7 @@ module OS
     # This can be compared to numerics, strings, or symbols
     # using the standard Ruby Comparable methods.
     def version
-      @version ||= Version.new(full_version.to_s[/10\.\d+/])
+      @version ||= Version.new(full_version.to_s[/^\d+\.\d+/])
     end
 
     # This can be compared to numerics, strings, or symbols