diff --git a/make_usd_card.sh b/make_usd_card.sh
index 1fbbd2c..8252d21 100755
--- a/make_usd_card.sh
+++ b/make_usd_card.sh
@@ -11,6 +11,8 @@ SD_MOUNT_POINT=$2
 [ "x$1" == "x" ] && display_usage && exit
 [ "x$2" == "x" ] && display_usage && exit
 
+[ ! "x$UID" == "x0"] && echo "run as root" && exit
+
 if $(df | grep /$ | grep -q "^$SD_DEV"); then
     echo "Target and current system device are the same. Can't do that!"
     exit