diff --git a/Formula/swfmill.rb b/Formula/swfmill.rb
index cd62baab5a..fda68ef006 100644
--- a/Formula/swfmill.rb
+++ b/Formula/swfmill.rb
@@ -5,6 +5,8 @@ class Swfmill <Formula
   homepage 'http://swfmill.org'
   md5 '88a634cad4d8d025c84c6e8916a8b1c4'
 
+  depends_on 'pkg-config'
+
   def install
     system "./configure", "--prefix=#{prefix}"
     system "make install"