&NA;A case of perianal Paget's disease associated with a cloacogenic carcinoma is presented. There was no clinical evidence of the Paget's disease, which was confined to a very small area. The points of particular interest were (1) the association of Paget's disease with a cloacogenic carcinoma, and (2) the dissimilarity between the pagetoid cells and the carcinoma cells. The histologic differences between the two cell types support the view that perianal Paget's disease and underlying carcinomas represent a multicentric reaction to an unknown stimulus