diff --git a/ext/openssl/ossl_asn1.c b/ext/openssl/ossl_asn1.c
index 3a07be5cc..dae3bb850 100644
--- a/ext/openssl/ossl_asn1.c
+++ b/ext/openssl/ossl_asn1.c
@@ -1304,7 +1304,7 @@ ossl_asn1obj_get_oid(VALUE self)
     val = ossl_asn1_get_value(self);
     a1obj = obj_to_asn1obj(val);
     len = OBJ_obj2txt(buf, sizeof(buf), a1obj, 1);
-    if (len < 0) {
+    if (len <= 0) {
 	ASN1_OBJECT_free(a1obj);
 	ossl_raise(eASN1Error, "OBJ_obj2txt");
     }