Cloning strategies were used to identify a gene termed glial cell line-derived neurotrophic factor receptor- (GDNFR-) related to GDNFR-␣. In situ hybridization was then used to map cellular expression of the GDNF-related trophic factor neurturin (NTN) and GDNFR- mRNA in developing and adult mice, and comparisons with GDNFR-␣ and RET were made. Neurturin is expressed in postnatal cerebral cortex, striatum, several brainstem areas, and the pineal gland. GDNFR- mRNA was more widely expressed in the developing and adult CNS, including cerebral cortex, cerebellum, thalamus, zona incerta, hypothalamus, brainstem, and spinal cord, and in subpopulations of sensory neurons and developing peripheral nerves. NTN colocalized with RET and GDNFR-␣ in ureteric buds of the developing kidney. The circular muscle layer of the developing intestines, smooth muscle of the urether, and developing bronchiolae also expressed NTN. GDNFR- was found in myenteric but not submucosal intestinal plexuses. In developing salivary glands NTN had an epithelial expression, whereas GDNFR- was expressed in surrounding tissue. Neurturin and GDNFR- were present in developing sensory organs. In the gonads, NTN appeared to be expressed in Sertoli cells and in the epithelium of the oviduct, whereas GDNFR- was expressed by the germ cell line. Our findings suggest multiple roles for NTN and GDNFR- in the developing and adult organism. Although NTN and GDNFR- expression patterns are sometimes complementary, this is not always the case, suggesting multiple modi operandi of GDNF and NTN in relation to RET and the two binding proteins, GDNFR-␣ and GDNFR-.