We report the first use of Onyx in the embolization of spinal tumors in 2 cases of aggressive vertebral hemangioma. In both cases, Onyx embolization provided effective preoperative tumor devascularization after the initial prolonged particulate embolization with Embospheres made little overall impact. Onyx enables a more rapid and visible embolization than particles and is less technically demanding than traditional liquid embolic agents, such as n-butyl cyanoacrylate.