diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index c54df055da..cd899d45c4 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -357,7 +357,7 @@ class Formula
   def self.installed
     return [] unless HOMEBREW_CELLAR.directory?
 
-    HOMEBREW_CELLAR.children.map do |rack|
+    HOMEBREW_CELLAR.subdirs.map do |rack|
       begin
         factory(rack.basename.to_s)
       rescue FormulaUnavailableError