Thirteen patients with carcinoma of the bladder have been treated by arterial infusion of doxorubicin hydrochloride pre-operatively. Teflon catheters 0.25 mm in diameter were inserted by the Seldinger technique and the tips were placed in the aorta between the origin of the inferior mesenteric artery and the aortic bifurcation. The doses administered ranged from 80 mgs to 250 mgs with an average of 125 mgs. A response rate of 69% was seen. In 3 cases tumours disappeared; in a further 6 patients some tumour regression was apparent. One patient died from cardiac insufficiency. Although this method of treatment remains to be fully evaluated, preliminary results suggest that it may be an effective pre-operative treatment.