diff --git a/src/GenericParser/DomainParser.purs b/src/GenericParser/DomainParser.purs
index 17b7e30..5a080ca 100644
--- a/src/GenericParser/DomainParser.purs
+++ b/src/GenericParser/DomainParser.purs
@@ -26,13 +26,14 @@ import GenericParser.Parser (Parser(..)
 label :: Parser DomainError String
 label = do
   pos <- current_position
+  maybeu <- tryMaybe $ char '_'
   maybel <- tryMaybe letter
   case maybel of
     Nothing -> Parser \_ -> failureError pos (Just InvalidCharacter)
     Just l -> do
       s <- tryMaybe ldh_str
       lastpos <- current_position
-      let labelstr = CU.singleton l <> maybe "" CU.fromCharArray s
+      let labelstr = maybe "" (\_ -> "_") maybeu <> CU.singleton l <> maybe "" CU.fromCharArray s
       if (S.length labelstr > max_label_length)
       then Parser \_ -> failureError pos (Just <<< LabelTooLarge $ S.length labelstr)
       else if (S.length labelstr > 1 && not (parse_last_char labelstr let_dig))