Twenty-one patients with prostate cancer underwent intermittent arterial infusion chemotherapy with an implanted reservoir and alteration of the intrapelvic blood flow. One internal iliac artery was embolized with steel coils so that the drugs would perfuse throughout the tumor through a single tube. Angiography performed after embolization showed distinct tumor vessels. Intensive radioisotope accumulation was demonstrated in the prostate gland at scintigraphy performed with technetium-99m macroaggregated albumin. Ten milligrams each of cisplatin and doxorubicin were injected once a week by means of puncture of the implanted reservoir. All patients had more than a 50% reduction in tumor size. The response rate to this treatment was good; six patients experienced complete response, and 13 had partial response. Two patients had progressive disease. With this technique, small doses of the anticancer agents reached the tumor in high concentrations. Results were good, with few side effects.