diff --git a/contrib/scripts/install_prereq b/contrib/scripts/install_prereq
index 17cbf030985a2c5e6373e779d05eb23c1c3d0e17..06eb05e71445877eae1c5e03617864368d106e4b 100755
--- a/contrib/scripts/install_prereq
+++ b/contrib/scripts/install_prereq
@@ -101,6 +101,7 @@ handle_debian() {
 		apt-get install aptitude
 	fi
 	extra_packs=`check_installed_debs $PACKAGES_DEBIAN`
+	$testcmd aptitude update
 	$testcmd aptitude install -y $extra_packs
 }