diff --git a/unrouted_handler.go b/unrouted_handler.go
index ae283d3..20e70ff 100644
--- a/unrouted_handler.go
+++ b/unrouted_handler.go
@@ -470,7 +470,7 @@ func (handler *UnroutedHandler) PatchFile(w http.ResponseWriter, r *http.Request
 			return
 		}
 		uploadLength, err := strconv.ParseInt(r.Header.Get("Upload-Length"), 10, 64)
-		if err != nil || uploadLength < 0 || uploadLength < info.Offset || uploadLength > handler.config.MaxSize {
+		if err != nil || uploadLength < 0 || uploadLength < info.Offset || (handler.config.MaxSize > 0 && uploadLength > handler.config.MaxSize) {
 			handler.sendError(w, r, ErrInvalidUploadLength)
 			return
 		}