A recently reported Y receptor that has been confusingly referred to as both Y5 and Y2b has now been designated as Y6 by the IUPHAR organization. Using random primed Y6 coding sequence as a hybridization probe we examined the mRNA expression pattern and gene distribution of the Y6 receptor in a variety of species. We detail the relative abundance of Y6 message in mouse and human tissues and report the apparent absence of message for this receptor in any rat tissues tested. We also document the presence of the Y6 gene in chicken, rabbit, cow, dog, mouse, monkey and human, but the complete absence of the Y6 gene in rat.