Ninteen patients with histologically proven superficial bladder cancer (Ta, T1) were treated with intravesical instillation of 30 mg of adriamycin (ADM) dissolved in 24 ml physiological saline plus 15 mg of verapamil (VR) (6 ml) every day for 10 days. In spite of the short period of treatment, 6 of the 18 evaluable patients (33.3%) showed complete response (CR) and a further 5 (27.8%) showed partial response (PR). Five of the 6 patients with CR were recurrent cases who had previously received prophylactic intravesical instillation chemotherapy including ADM. Irritative urinary symptoms were observed in 11 of the 19 patients (57.9%). However, these symptoms were mild in the majority of patients and the treatment was completed without interruption in all but 1 patient. There was no significant absorption of ADM and VR into the systemic circulation. No clinical evidence of systemic toxicity was observed. These results suggest that combination of ADM and VR has a possibility to be a useful prophylactic intravesical instillation chemotherapy after endoscopic resection of not only primary but also recurrent chemoresistant bladder cancers.