The clinical experience with five patients selected for embolization of cerebral arteriovenous malformations with bucrylate (isobutyl-2-cyanoacrylate) during surgery is described. Bucrylate embolization was used to obliterate one arteriovenous malformation with a dominant nutrient arterial network, and to facilitate surgical resection in two other cases. The extent of the embolization in one of these cases was limited because of segmental perfusion of the AVM nidus by different nutrient arteries. Histological examination of this arteriovenous malformation, resected 56 days after embolization, suggested bucrylate has minimal histotoxicity. Two arteriovenous malformations were found at operation to be unsuitable for embolization because of technical problems with access and exposure of nutrient arteries, and also because of vagaries in the angiographic data before surgery. In two cases, rapid polymerization of bucrylate resulted in gluing of the injection catheters into the arterial lumen. Two patients experienced transient postoperative neurological deficits after bucrylate embolization. Because of the potential hazards of the technique, direct bucrylate embolization of cerebral arteriovenous malformations should only be considered for those lesions felt unsuitable for direct microsurgical excision, and where facilities exist for recording angiographic data before surgery.