diff --git a/check_updates.sh b/check_updates.sh
index 1d4b9df..a4c9d20 100755
--- a/check_updates.sh
+++ b/check_updates.sh
@@ -5,6 +5,12 @@ PATH="$PATH:/usr/sbin:/sbin"
 TMP_FILE=$(mktemp)
 MAIL=$(mktemp)
 
+PORTAGE_RUNING=$(pgrep emerge)
+if [ "${PORTAGE_RUNING}" ]; then
+       echo "Error: another emerge is already running, exiting"
+       exit 1
+fi
+
 PORTAGE_QUIET='1'
 
 eix-sync 1>/dev/null 2>${TMP_FILE}