Urachal remnants were obtained at autopsy from 10 males and 15 females in order to determine whether prostatic specific antigen (PSA) is present in that tissue. Immunohistochemical staining was carried out using a commercially available antibody to PSA. Four cases (three females and one male) showed focal positive reaction of PSA, predominantly in narrow glandular structures of metaplastic origin. Therefore, it cannot be excluded that PSA might occur in urachal adenocarcinomas. PSA-staining is evidently not confined exclusively to tissue originating in the prostate.