Sarcomas of the kidney are highly malignant neoplasms. Abnormal vascularity can be detected in almost all types of sarcomas, but arteriovenous shunting, pooling of contrast material, and tumor staining are seldom present. Extension to renal vein and inferior vena cava may occur. While angiographic findings in our seven cases of renal sarcomas were nonspecific, this diagnosis should be considered in a relatively hypovascular neoplasm especially when the capsular arteries contribute considerably to the vascular supply. Nevertheless, statistically the most likely diagnosis of a hypovascular mass is renal cell carcinoma. Angiographic studies do not alter the management of the patient but merely suggest the diagnostic possibility of sarcoma. Angiographic diagnosis of different histologic types of sarcomas is not possible.