We report 2 cases of angiosarcoma of the prostate gland. The patients were 42 and 60 years old, which is in sharp contrast to the presentation of rhabdomyosarcoma, which occurs primarily in children. Immunoperoxidase staining for factor VIII associated antigen was positive in both cases, and was particularly useful in confirming the diagnosis in 1 case that was otherwise poorly differentiated. One patient is alive without evidence of recurrence 2 years after surgical excision, while the other presented with unresectable tumor and died 6 months after presentation. Angiosarcoma represents less than 2 per cent of sarcomas of the prostate but it should be considered in the differential diagnosis of poorly differentiated sarcomas, particularly those occurring in adults.