diff --git a/Library/Formula/slony.rb b/Library/Formula/slony.rb
index 1761445eb4ae..90ad3fc3ab27 100644
--- a/Library/Formula/slony.rb
+++ b/Library/Formula/slony.rb
@@ -12,7 +12,7 @@ def message; <<-EOS.undent
     EOS
   end
   def satisfied?
-    which 'pg_config'
+    which 'postgres'
   end
   def fatal?
     true