A 23-month-old infant with an extensive dural arteriovenous malformation (AVM) developed a heart murmur and cardiomegaly. The AVM involved the occipital and suboccipital dura mater and the tentorium, bilaterally. We embolized the AVM with Gelfoam and polyvinyl alcohol particulates, subtotally resected it, and embolized residual vessels with isobutyl cyanoacrylate. In spite of this extensive therapy, the malformation was not totally eradicated and an occipital pial AVM developed. This infant and the eight infants with posterior dural AVMs reported previously emphasize the difficulty of eradicating these lesions in infancy. We contrast the clinical features and therapy of infants and adults with posterior dural AVMs. Infants develop heart failure and cranial bruits because of arteriovenous shunts, whereas adults complain of headache and intracranial bruits. Infants need therapy to prevent progressive heart failure, intracranial hypertension, and perhaps cerebral ischemia. Ligation of arterial tributaries is inadequate therapy for these lesions. Embolization and resection of the malformation, when feasible, offers the best chance of curing posterior dural AVMs with extensive arterial tributaries.