A review of experience with urine cytology in the diagnosis and follow up of bladder cancer at Roswell Park Memorial Institute from 1971 to 1981 is reported. All patients had biopsy-proven transitional cell carcinoma of the bladder. A total of 677 patients underwent 2,877 cytological evaluations. Of these, 317 patients had concomitant cystoscopy, cytologic evaluations and bladder biopsies. A total of 1,091 evaluations were performed in this group. The overall incidence of positive cytology in the presence of biopsy-proven bladder tumor (all grades included) was 74.4%. A linear correlation is present with grade, stage and positive cytology; high-grade tumors and carcinoma-insitu showed 89.9% and 96.9% incidence of positive cytology, respectively. Grade II tumors showed a 64% incidence of positive cytologies. Regarding correlation with the pathological stage, submucosal involvement of the urothelium was associated with a 62% incidence of positive exfoliative urine cytology, while 80% of tumors invading the bladder muscle were found to have a positive cytology.