diff --git a/check_pg_streaming_replication b/check_pg_streaming_replication
index e379c9a..cdab14e 100755
--- a/check_pg_streaming_replication
+++ b/check_pg_streaming_replication
@@ -112,7 +112,7 @@ id "$PG_USER" > /dev/null 2>&1
 [ $( echo "$PG_DEFAULT_PORT"|grep -c -E '^[0-9]*$' ) -ne 1 ] && "UNKNOWN : Postgres default master TCP port must be an integer." && exit 3
 
 # If PG_DB is not provided with -D parameter, use PG_USER as default value
-[ -z "$PB_DB" ] && PG_DB="$PG_USER"
+[ -z "$PG_DB" ] && PG_DB="$PG_USER"
 
 function psql_get () {
 	echo "$1"|su - $PG_USER -c "$PSQL_BIN -d "$PG_DB" -t -P format=unaligned"