Angiosarcoma is a rare malignant tumor accounting for less than 2% of all soft tissue sarcomas. Primary angiosarcoma of the kidney is an extremely rare but a highly aggressive tumor with poor prognosis. Patients frequently have symptoms of flank pain, hematuria, or abdominal mass. Surgery is the mainstay of treatment followed by radiation with or without chemotherapy. We describe the case of a 61-year-old man with rupture of a primary renal angiosarcoma with clinical features of disseminated intravascular coagulation (DIC). The patient underwent radical nephrectomy, and DIC including uncontrolled thrombocytopenia was resolved after the operation. We suggest that renal angiosarcoma is a cause of extensive retroperitoneal hematomas with clinical features of DIC.