diff --git a/src/hangulin.c b/src/hangulin.c
index f02cad8..4e1a7f8 100644
--- a/src/hangulin.c
+++ b/src/hangulin.c
@@ -1515,7 +1515,7 @@
     int i;
 
     if ((i = han_index(h, low)) >= 0
-	&& i < sizeof(ks_table1)/sizeof(ks_table1[0]))
+	&& i < (int)(sizeof(ks_table1)/sizeof(ks_table1[0])))
     {
 	*fp = ks_table1[i][0];
 	*mp = ks_table1[i][1];