Further recurrence of superficial bladder cancer after transurethral resection is frequent in patients who have already experienced recurrence. In an attempt to prevent or delay further recurrences in such patients, the effect of preoperative doxorubicin instillation was investigated. A total of 51 patients with recurrent superficial bladder cancer were randomized to receive either TUR alone or TUR with preoperative doxorubicin instillation. Doxorubicin was administered twice a week for 3 weeks before TUR surgery. An objective response (CR + PR) of the tumors was observed at operation in 12 of 25 (48%) evaluable doxorubicin-treated patients. Chemical cystitis was seen in 32% of the patients. Further recurrence after TUR was observed in 13 of 25 (52%) patients in the doxorubicin group, as against 15 of 23 (65%) evaluable patients in the control group. The mean disease-free interval was significantly longer (11.8 as against 7.1 months) in the doxorubicin group. These preliminary results suggest that preoperative doxorubicin instillation might be effective for prolongation of the disease-free interval in patients with recurrent bladder cancer.