diff --git a/tools/pip-requires b/tools/pip-requires
index 631245f0..b46e07a1 100644
--- a/tools/pip-requires
+++ b/tools/pip-requires
@@ -4,6 +4,7 @@
 # Development
 netifaces
 termcolor
+pyyaml # reading data files
 
 # Testing
 nose # for test discovery and console feedback