A total of 7 patients with high grade, T3a (Stage B2) bladder cancer were treated with external radiation therapy and interstitial iridium implantation from May 1986 through March 1988. Follow-up has ranged from nineteen to sixty-one months with a median of forty months. One patient has required a cystectomy and is currently free of disease, and 1 patient has had recurrence of his cancer and metastatic carcinoma has developed; 5 are free of disease and have maintained their usual state of bladder function. Iridium implantation maintains bladder function and is effective therapy for selected individuals with localized, muscle-invading bladder cancer.