Juvenile nasopharyngeal angiofibromas are vascular tumors that may make resection difficult and potentially dangerous. Preoperative embolization is frequently used to decrease surgical morbidity and blood loss. Embolization has typically been performed via a transarterial route using a variety of embolic materials. The authors present a case in which endoscopic assistance was used for direct transnasal tumor puncture and intratumoral embolization using the liquid embolic agent Onyx. In this case there was excellent infiltration of the parenchymal vasculature with complete angiographic obliteration. There were no complications related to the embolization. The tumor was resected with minimal blood loss. To the authors' knowledge, there have been no previous reports of this novel direct intratumoral embolization technique using endoscopic guidance.