diff --git a/qclib.spec b/qclib.spec
index 2c94f84..113f3a4 100644
--- a/qclib.spec
+++ b/qclib.spec
@@ -10,6 +10,7 @@ BuildRequires:	make
 BuildRequires:	gcc
 BuildRequires:	glibc-static
 BuildRequires:	doxygen
+BuildRequires:	which
 
 %description
 %{summary}.