A 1 U/ml solution of bleomycin sulfate in physiologic saline solution was injected intralesionally in 38 patients, and was compared with physiologic saline solution injection into paired warts in the same patient. No patient received more than 2 ml of bleomycin. Ninety-seven of 143 warts (67.8%) showed complete resolution after one or two bleomycin injections, while 25 warts (17.5%) showed incomplete resolution. Bleomycin local injection failed to elicit any therapeutic response in 21 warts (14.7%). The cure rate was 77% for warts on the extremities, 71.4% for periungual warts, and 47.6% for the plantar warts. The responsive warts showed hemorrhagic eschars that healed without scarring. It is concluded that this form of treatment for resistant warts, up to the dose used, is safe, reliable, and accepted by the patient.