diff --git a/doc/INSTALL b/doc/INSTALL
index 73c33b5485d..254b7e7b5a0 100644
--- a/doc/INSTALL
+++ b/doc/INSTALL
@@ -14,6 +14,7 @@ You need the following software installed:
     * Reportlab pdf generation library for python
     * lxml python module
     * pytz python module
+    * PyYaml python module (install with: easy_install PyYaml)
 
 Some dependencies are only required for specific purposes: