Protocadherins constitute a large family of transmembrane proteins primarily involved in weak homophilic adhesion in the brain and several other tissues. In a screen for potential regulators of kidney development, we have identified Pcdh19, a poorly characterized member of the delta-protocadherin subfamily. Here, we report the spatio-temporal expression pattern of Pcdh19 during mouse embryonic development. In midgestation embryos, Pcdh19 mRNA was detected in the mesonephros and in the neuroepithelium of the forebrain and midbrain. At later stages, Pcdh19 was expressed in other neural tissues such as the neural retina, nasal epithelium and spinal cord, as well as in the collecting duct and differentiating nephrons of the metanephros, in the glandular stomach, the exocrine pancreas and the hair follicles. Hence, the Pcdh19 gene is developmentally regulated during mouse organogenesis and shows a unique expression profile among protocadherins.