Vascular lesions in connection with fractures of the pelvis frequently cause massive internal haemorrhage and are the most common cause of death among these patients. As a rule, the first 48 hours after the injury are considered to be the most critical as regards the risk of haemorrhage. A case of a man aged 20 years with a pelvic fracture is presented here. More than five months after the fracture, severe haemorrhage endangering life occurred following incision of an apparently subcutaneous haematoma in the left flank. The importance of continued control of patients with known retroperitoneal haematomata after pelvic fractures is emphasized.