diff --git a/programs/util/pem2der.c b/programs/util/pem2der.c
index 4a25f21..5dd367a 100644
--- a/programs/util/pem2der.c
+++ b/programs/util/pem2der.c
@@ -189,7 +189,7 @@
     memset(buf, 0, sizeof(buf));
     memset(der_buffer, 0, sizeof(der_buffer));
 
-    if (argc == 0) {
+    if (argc < 2) {
 usage:
         mbedtls_printf(USAGE);
         goto exit;