diff --git a/src/util/virconf.c b/src/util/virconf.c
index f2d543c4ff..eb55a1a16b 100644
--- a/src/util/virconf.c
+++ b/src/util/virconf.c
@@ -545,7 +545,7 @@ virConfParseValue(virConfParserCtxtPtr ctxt)
                          _("numbers not allowed in VMX format"));
             return NULL;
         }
-        type = (c_isdigit(CUR) || CUR == '+') ? VIR_CONF_ULONG : VIR_CONF_LONG;
+        type = (CUR == '-') ? VIR_CONF_LONG : VIR_CONF_ULONG;
         if (virConfParseLong(ctxt, &l) < 0)
             return NULL;
     } else {