diff --git a/skeletons/OCTET_STRING_oer.c b/skeletons/OCTET_STRING_oer.c
index b30dbe7..8df3356 100644
--- a/skeletons/OCTET_STRING_oer.c
+++ b/skeletons/OCTET_STRING_oer.c
@@ -116,7 +116,7 @@
 
     if(!st) ASN__ENCODE_FAILED;
 
-    ASN_DEBUG("Encoding %s %d as OCTET STRING", td ? td->name : "", st->size);
+    ASN_DEBUG("Encoding %s %zu as OCTET STRING", td ? td->name : "", st->size);
 
     if(ct_size >= 0) {
         /*
@@ -144,7 +144,7 @@
         if(st->size != unit_bytes * (size_t)ct_size) {
             ASN_DEBUG(
                 "Trying to encode %s (%zu bytes) which doesn't fit SIZE "
-                "constraint (%d)",
+                "constraint (%zu)",
                 td->name, st->size, ct_size);
             ASN__ENCODE_FAILED;
         }