Between May 1979 and July 1983, 217 consecutive patients with documented primary bladder tumors invading muscle were evaluated to determine the fate of patients with conservatively treated muscle-infiltrating bladder cancer. The disease was re-staged by urine cytology, bimanual examination with the patient under anesthesia and transurethral biopsy or resection. Of the 217 patients 172 underwent total or partial cystectomy and 45 (21 per cent, 37 with stage T2, 7 with stage T3a and 1 with stage T4 disease) did not because re-staging showed no residual tumor (stage T0) in 20, carcinoma in situ in 17, stage T1 tumor in 4 and local stage T2 cancer in 4. The median followup was 5.1 years (range 3 to 7 years). Of the 45 patients 30 (65 per cent) are free of tumor or have required transurethral resection and intravesical therapy for recurrent tumors but cystectomy has not been necessary. Of the 15 failures 11 underwent cystectomy 9 to 30 months after re-staging (7 are alive and 4 died of disease) and 4 are alive with metastatic disease (2 with negative bladder biopsies). Re-staging in the 4 patients who died showed stage T0 disease in 2, carcinoma in situ in 1 and stage T2 tumor in 1. The over-all survival rate was 82 per cent (37 of 45) and it was 67 per cent (30 of 45) for patients with a functioning bladder. The data suggest that endoscopic re-staging may identify a subset of patients with limited muscle-infiltrating bladder tumors that can be managed conservatively without immediate cystectomy.