diff --git a/contrib/scripts/install_prereq b/contrib/scripts/install_prereq
index 17cbf03098..06eb05e714 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
 }