Twenty-eight consecutive patients with extremity osteosarcoma (24 stage II, four stage III) received their entire preoperative course of chemotherapy intraarterially in order to maximize local drug concentration and tumor shrinkage to facilitate limb-sparing resection. Eighteen tumors were located in the femur, seven in the tibia, two in the humerus, and one in the fibula. Most patients underwent two catheterizations; thus there was a total of 51 procedures. The average duration of each infusion was 10.4 days. There were eight procedure-related complications, but none precluded completion of intraarterial chemotherapy. Limb-sparing surgery was performed on 25 patients. At a mean follow-up of over 2 years, there was one local recurrence. Among limb-salvage patients with stage II disease, 90% (18 of 20) survived and 75% (15 of 20) are disease-free. Compared with patients from previous studies, this technique permits a high percentage of patients with osteosarcoma to undergo limb-sparing resection without compromise of local disease control or survival.