Twenty-two patients with vesical urothelial carcinoma associated with prostatic carcinoma were reviewed. They represented 1.5% of the bladder and prostatic tumours treated in our department within a 12-year period from 1968 to 1979. Their management included several treatment policies, based on the separate assessment of each tumour variant. For non-infiltrating bladder tumours, transurethral tumour resection was combined with hormonal treatment, external radiotherapy or resection of the prostate depending on the stage of the prostatic tumour. Radical cystoprostatectomy was performed for two cases of infiltrating bladder tumour with well localised prostatic tumours. A conservative primary approach seems justifiable in the management of double carcinoma of the bladder and prostate. The coincidence of bladder urothelial carcinoma and prostatic carcinoma per se is not an adverse prognostic factor; prognosis is more closely related to the pathological stage and grade of the bladder tumour. Cystoprostatectomy for patients with infiltrating bladder tumours could be curative, in selected cases, for the prostatic cancer as well.