The incidence and features of malignant primary multiple (MPM) neoplasias found in clinical urological patients have been analyzed so as to determine the actual magnitude of the problem and to obtain a better knowledge of this disease. For this reason, case histories of patients with MPMN, where at least one of the involved neoplasia was urological, were retrospectively studied. The study included a 9-year follow-up period and followed the Warren and Gates inclusion criteria. The number of MPMN patients was 23, representing an incidence of 6.1% among patients with urological neoplasias. Mean age at the time of discovery of the second tumour was 77.1 years. In the 15 patients with metachronic tumours, the time interval between the first and second tumours ranged between 1 to 25 years (average 5.4 years). The most frequently observed tumour association was bladder transitional carcinoma and prostate adenocarcinoma. The cause of death was always the second neoplasia.