WE report here the cloning of a novel form of the murine glial cell line-derived neurotrophic factor (GDNF) receptor. Northern blot analyses of various mouse tissues, including whole brain, demonstrated the existence of multiple transcripts of GDNF receptor. Screening of an adult mouse liver cDNA library yielded two isoforms of the receptor. One of the forms (β) shows a high degree of homology with other mammalian GDNFR-α and the other novel form (β) is identical to the α form except for a deletion of five amino acids. These two forms do not share high sequence homologies with the recently isolated neurturin receptor. Both the α and β forms are expressed in various murine tissues but not in muscle.