Twelve patients with large arteriovenous malformations (AVMs) were subjected to endovascular embolization followed by surgery. Of the 12 patients, 9 were males and 3 females. Their age ranged from 11 to 37 years. Eleven AVM nidi were more than 6 cm in diameter and one AVM, located in a crucial brain area, was 4 cm in diameter. More than 70% of the AVM masses were excised in 11 of the patients, while under 50% was excised in the remaining patient. Complete excisions of the lesions were achieved in all 12 patients 7-10 days after endovascular embolization. No new major neurological deficits occurred. The results showed that the cerebral AVMs can be effectively operated on after endovascular embolization.