Intravascular sarcoma thrombi were histologically evident in 2% of 470 patients with soft tissue or bone sarcoma treated during the last 3 years. Vascular invasion by sarcoma in our series was associated with an aggressive disease and short-term overall survival. In all the cases there was a large or locally advanced primary high grade sarcoma, and in all but one case, where preoperative chemotherapy was administered, the response was far from satisfactory. The post-operative course in 70% of the patients was characterized by early systemic spread, and a median overall survival of 9.5 months. The gloomy prognosis of our patients does not necessarily stem only from the presence of vascular invasion, but may also be related to other factors as histologic grade and tumor size. However, as compared to similar cases in our patient population, which did not show vascular invasion, the course here was more violent and short.