We present a new message authentication code. It is based on a two trail construction, which underlies the unkeyed hash function RIPEMD-160. It is in comparison with the MDx-MAC based on RIPEMD-160, much more efficient on short messages (that is on messages of 512 or 1024 bits) and percentage-wise a little bit more efficient on long messages. Moreover, it handles key-changes very efficiently. This positive fact remains if we compare our Two-Track-MAC with HMAC based on RIPEMD-160.