diff --git a/mgmt/main.c b/mgmt/main.c
index 3343d21..20d7bf8 100644
--- a/mgmt/main.c
+++ b/mgmt/main.c
@@ -505,7 +505,7 @@ static void confirm_name_rsp(int mgmt_sk, uint16_t op, uint16_t id,
 
 	if (len != sizeof(*rp)) {
 		fprintf(stderr,
-			"hci%u confirm_name rsp length %u instead of %u\n",
+			"hci%u confirm_name rsp length %u instead of %zu\n",
 			id, len, sizeof(*rp));
 		return;
 	}
diff --git a/plugins/mgmtops.c b/plugins/mgmtops.c
index 5383864..6d5862e 100644
--- a/plugins/mgmtops.c
+++ b/plugins/mgmtops.c
@@ -1245,7 +1245,7 @@ static void mgmt_device_found(int sk, uint16_t index, void *buf, size_t len)
 	uint32_t cls;
 
 	if (len != sizeof(*ev)) {
-		error("mgmt_device_found length %u instead of expected %u",
+		error("mgmt_device_found length %zu instead of expected %zu",
 							len, sizeof(*ev));
 		return;
 	}