We report a prospective study of 136 patients with biopsy proved bladder tumor who underwent 311 evaluations with cystoscopy, urinary cytology, bladder washing and, when indicated, bladder biopsies. Cytology results from bladder washings were superior to routine urinary cytology studies in detecting abnormal cells. Also, there was a significant increase in the number of positive cytology studies in bladder washings from patients with no evidence of tumor by cystoscopy but who had biopsy proved dysplasia. Multiple selective bladder biopsies showed a higher incidence of mucosal abnormalities if the primary tumor was of a higher grade.