The authors present two cases of dural arteriovenous malformations (AVM's) that developed at the site of previous suboccipital craniectomies. No other cases of delayed postoperative dural AVM's have been reported. Congenital and acquired dural AVM's are discussed, with reference to the similarity between postoperative dural AVM's and traumatic dural AVM's. Embolization is recommended in selected cases where the arterial supply is primarily from the external carotid system.