diff --git a/model/model.go b/model/model.go
index 6783054..bb9255a 100644
--- a/model/model.go
+++ b/model/model.go
@@ -41,7 +41,10 @@ func (q *Model) Values(i interface{}) url.Values {
 	iVal := reflect.ValueOf(i).Elem()
 	typ := iVal.Type()
 	for i := 0; i < iVal.NumField(); i++ {
-		values.Set(strings.ToLower(typ.Field(i).Tag.Get("json")), PyConvert(iVal.Field(i)))
+		tag := typ.Field(i).Tag.Get("json")
+		if tag != "-" {
+			values.Set(strings.ToLower(tag), PyConvert(iVal.Field(i)))
+		}
 	}
 	return values
 }