diff --git a/README b/README
index c8757ff..8696241 100644
--- a/README
+++ b/README
@@ -19,6 +19,7 @@ Many little improvements have been made to i3lock over time:
 
 Requirements
 ------------
+- pkg-config (or you can rewrite the Makefile by hand if you want to avoid it)
 - libxcb
 - libxcb-util
 - libpam-dev