Eleven abnormal findings of digital subtraction angiography were analyzed in 25 patients with bone sarcoma and in 23 patients with soft tissue sarcoma. The relation between digital subtraction angiographic findings and the histologic effect of chemotherapy was evaluated. Digital subtraction angiography was performed with the patient under local anesthesia with the Seldinger technique, using an ADVANT X unit. Contrast medium was injected at a rate of 4 to 6 ml per second, with the usual single bolus dose of approximately 6 to 8 ml. Eleven abnormal findings included tumor stain, hypervascularity, arterial distortion, vascular stretch, arterial dilatation, arteriovenous shunt, arterial encasement, occlusion, blood pool, caliber with irregular wall, and dilatation of draining vein. Each finding after preoperative chemotherapy was compared with that before chemotherapy and divided into three grades; Grade 1, not effective; Grade 2, effective; and Grade 3, very effective. Angiographic Grades 2 and 3 were defined as responders. The histologic effect was examined and scored according to the modified classification proposed by Huvos. Histologic Grades 1 and 2 were classified as nonresponders and Grades 3 and 4 as good responders. In bone sarcomas, hypervascularity and tumor stain were seen in all patients. In soft tissue sarcomas, tumor stain was shown in all 23 patients and hypervascularity was seen in 21 patients. Tumor stain, hypervascularity, vascular stretch, and arterial encasement were correlated closely with histologic findings and showed an accuracy equal to or greater than 70%. When these four findings changed to angiographic Grade 3 after preoperative chemotherapy, 90% of patients had good histologic outcome.