diff --git a/libs/freetdm/src/ftdm_io.c b/libs/freetdm/src/ftdm_io.c
index d99561566c..932ce30aa7 100644
--- a/libs/freetdm/src/ftdm_io.c
+++ b/libs/freetdm/src/ftdm_io.c
@@ -4735,7 +4735,7 @@ static void print_core_usage(ftdm_stream_handle_t *stream)
 
 static unsigned long long ftdm_str2val(const char *str, val_str_t *val_str_table, ftdm_size_t array_size, unsigned long long default_val)
 {
-	int i;
+	ftdm_size_t i;
 	for (i = 0; i < array_size; i++) {
 		if (!strcasecmp(val_str_table[i].str, str)) {
 			return val_str_table[i].val;
@@ -4746,7 +4746,7 @@ static unsigned long long ftdm_str2val(const char *str, val_str_t *val_str_table
 
 static const char *ftdm_val2str(unsigned long long val, val_str_t *val_str_table, ftdm_size_t array_size, const char *default_str)
 {
-	int i;
+	ftdm_size_t i;
 	for (i = 0; i < array_size; i++) {
 		if (val_str_table[i].val == val) {
 			return val_str_table[i].str;