Background: This randomized trial was conducted to compare the efficacy and side effects of intravesical mitoxantrone instillation with those of doxorubicin in superficial bladder cancer following transurethral resection. Methods: Sixty-three patients were randomized into mitoxantrone and doxorubicin groups. Most of the patients enrolled were elderly people (mean age, 71 years). The instilled doses of doxorubicin and mitoxantrone were 30 and 14 mg, respectively. Disease recurrence and side effects were compared using Fisher's exact test. The interval to recurrence was shown by Kaplan-Meier survivorship curves, and the log-rank test was used to compare the time to recurrence. Results: The median follow-up period was 36 months. Thirty-three patients received mitoxantrone, whereas 30 patients used doxorubicin. The recurrence rate in the doxorubicin group was 30% (95% CI: 19.8%-38.8%), while it was 27.3% (95% CI: 17.5%-36.8%) in the mitoxantrone group. The median recurrence-free survival in the mitoxantrone group and in the doxorubicin group was 22 and 20 months, respectively (p=0.580). Higher recurrence rates were found for Grade III and multiple primary tumors. There was no significant difference in response rates (p = 0.784). The incidence of side effects was 20% in the doxorubicin group and 21.2% in the mitoxantrone group. However, the difference was not significant (p > 0.99). Conclusions: The results revealed that the efficacy and side effects of mitoxantrone were similar to those of doxorubicin. Especially for patients with pulmonary tuberculosis or aged patients with primary bladder tumors, mitoxantrone and doxorubicin may be the tolerable and effective intravesical agents.