Eighteen patients with T1 transitional cell carcinoma of the urinary bladder were submitted to transurethral resection of the tumor, followed by Cobalt therapy (5,500 rads to the pelvis and 6,500 rads to the bladder in six weeks). The recurrence rate at three years follow-up was 33% (6/18). Recurrence of transitional cell carcinoma of the urinary bladder is a well known condition in stage O and A, even when low grade is present. Recurrence rates at one year as high as 84% (Loening et al., 1983) are reported in the current literature. In recent years many studies have been performed which were oriented to the use of intravesical chemotherapy in order to reduce the recurrence rate (Adolphs and Bastian, 1983; Huland, 1983; Loening et al., 1983; National Bladder Cancer Collaborative Group A, 1977; Rodriguez and Caserta, 1983; Zincke et al., 1983) of this tumor. We started a protocol on treatment of the transitional cell carcinoma of the urinary bladder in 1963. The protocol calls for transurethral resection of the tumor followed by Cobalt therapy. This is an interim report on stage T1 (stage A) with such a treatment.