Reports of a dramatic decrease in tumor recurrence and regression of muscle invasive disease with oral bacillus Calmette-Guerin prompted us to conduct a randomized prospective comparison of oral bacillus Calmette-Guerin with the standard intravesical plus percutaneous therapy. Oral therapy consisted of 200 mg. Tice bacillus Calmette-Guerin 3 times each week. Intravesical and percutaneous Tice bacillus Calmette-Guerin at a dose of 50 mg. was given weekly for 6 weeks, at 8, 10 and 12 weeks, then at 6 months and every 6 months thereafter. Minimal side effects confirmed the safety of oral bacillus Calmette-Guerin. Tumor recurrence was documented in 21 of 33 oral bacillus Calmette-Guerin patients (64%) and 18 of 55 (33%) who received intravesical plus percutaneous therapy (p less than 0.002, chi-square test). We were unable to demonstrate any antitumor activity of oral bacillus Calmette-Guerin in this study.