Purpose: To determine the safety and efficacy of internal maxillary artery (IMA) and facial artery polyvinyl alcohol (PVA) embolization for treatment of refractory idiopathic epistaxis. Materials and Methods: From 1998-2011, 84 patients were referred for endovascular treatment of intractable idiopathic epistaxis. PVA (range, 180-300 μM) particles were used in all cases. One case required microcoils to prevent nontarget embolization. Medical records were reviewed for early recurrences and complications, which were correlated with the number of vessels receiving embolization using the Mantel-Haenszel χ2test for linear association; P<.05 was accepted for significance. Results: Vessels chosen for embolization were unilateral IMA in 8 patients, bilateral IMAs in 35 patients, bilateral IMAs with one facial artery in 32 patients, and bilateral IMAs and bilateral facial arteries in 9 patients. Early (<30 d) rebleeding requiring therapy occurred in nine patients (11%). Minor complications occurred in 22 patients (26%) and included mild facial or jaw pain, facial edema, headache, and transient ischemic attack. There was one major complication that consisted of facial skin sloughing and mild lip ulceration in a patient who had embolization of both IMAs and both facial arteries. A linear association was found when the number of vessels receiving embolization was correlated with both the rates of early recurrence (inversely, P=.04) and minor complications (P=.004). Conclusions: An initial treatment strategy involving embolization of bilateral IMAs with or without embolization of facial arteries for refractory idiopathic epistaxis is safe and effective. Additional facial artery embolization reduces the risk of early recurrence but increases the risk of minor complications.