OBJECTIVE: To compare the efficacy of intravesical bacillus Calmette-Guerin (BCG) immunotherapy vs. chemotherapy (mitomycin-C, epirubicin, and thiotepa) in superficial bladder cancer after transurethral transection of a bladder tumor (TUR-BT). MATERIALS AND METHODS: We performed a retrospective chart review of patients with superficial bladder cancer between September 1995 and October 2004. In total, 146 patients were eligible for our analysis. Intravesical therapy after TUR-BT was arranged. Recurrence, progression, survival rates, and adverse events were analyzed. RESULTS: In the BCG group, 16.3% of patients experienced recurrences within 2 years compared to 18.8% in the chemotherapy group (p=0.715). The overall progression rate was 7.5%. The overall and cancer-specific mortality rates at 5 years were 32.4% and 2.9%, respectively. More adverse events were found in the BCG group (18.3%) than in the chemotherapy group (12.1%) (p=0.294). CONCLUSION: We failed to show the superiority of intravesical BCG immunotherapy over chemotherapy in preventing recurrence of or mortality from superficial bladder cancer. In addition, intravesical BCG immunotherapy provoked more adverse events than did chemotherapy.