We recently cloned µ-protocadherin, a developmentally regulated cell adhesion molecule that contains an extracellular region with four cadherin-like ectodomains, and a triply repeating mucin domain in its longer isoform. Expression of µ-protocadherin in L929 cells resulted in cellular aggregation, confirming its role in intercellular adhesion. We now identify the human µ-protocadherin orthologue and study its distribution in vivo and its targeting in polarized epithelia. Blast searches and fluorescent in-situ hybridization analysis based on human-mouse synteny reveal that µ-protocadherin maps to 11p15.5, matching a previously identified gene called MUCDHL. At least three different splicing isoforms exist for MUCDHL that vary in expression in the fetal kidney. µ-protocadherin is apically expressed along the brush border of the proximal convoluted tubule of the adult kidney. Transfection of truncated forms of µ-protocadherin into polarized MDCK cells reveals that the Nterminus is essential for this targeting to the apical surface. These results suggest that while human µ-protocadherin may mediate a homotypic adhesive interaction, it may have additional functions in terminally differentiated epithelia.