A BAVM consists of tangled masses of tortuous arteries and veins that have no intervening capillaries. BAVMs often extend from brain parenchyma into the subarachnoid space. BAVMs often cause hemorrhages. In the current case, the girl was feeling fine on the morning before her death, and she went to school. Around noon, she complained of nausea and a headache. She vomited twice, but her temperature was apparently normal. At around 6:00 pm she went to bed. She was found dead the next morning, with her legs hanging over the side of the bed. An external and internal exam showed no traumatic lesions. Her brain, however, showed massive edema. On brain cut sections, an intracerebral hemorrhage with secondary necrosis was found around the left lateral ventricle, extending inside the ventricle. Microscopically, the lesion was composed of various caliber thick-walled vascular channels surrounded by intervening reactive cerebral parenchyma, with gliosis and hemosiderin deposits. Death was attributed to cerebral arteriovenous rupture, and manner of death was ruled natural. BAVMs are congenital vascular lesions that apparently affect less than 0.7 percent of the population. Approximately 20 percent of these BAVMs are detected in patients less than 21 years old, including 8 percent in children 10 years old or younger. BAVMs discovered in childhood tend to be larger and are more likely to present initially with intracranial hemorrhage than those that show symptoms in adulthood. The current case is a reminder that BAVMs are a possible cause of sudden and unexpected deaths in children. Forensic pathologists should be able to recognize this lesion and differentiate it from the other types of vascular malformation. 1 table, 1 figure, and 7 references