Results of a randomized prospective study are reported in which mitomycin C, Tice bacillus Calmette-Guerin (BCG) and RIVM-BCG were compared in 437 patients with primary or recurrent pTa and pT1 bladder tumors, including carcinoma in situ. The followup (or time in study) varied from 2 to 81 months (mean 36 months). After complete transurethral resection of all visible tumors the patients were treated with 30 mg. mitomycin C once a week for 4 consecutive weeks and thereafter every month for a total of 6 months, and 5 x 10(8) colony-forming units Tice BCG or RIVM-BCG once a week for 6 consecutive weeks. For papillary tumors mitomycin C and RIVM-BCG treatments were equally effective (p = 0.53), and mitomycin C was more effective than Tice BCG therapy (p = 0.01).