Endovascular management of maxillary arteriovenous malformation (AVMs) can be complex. Transarterial, transvenous, and direct puncture embolization has been described. The authors report the case of a 9-year-old girl with a hemorrhagic maxillary AVM, which has been treated by transvenous embolization after failure of transarterial embolization. The venous pouch was catheterized with a detachable tip microcatheter and occluded by slow Onyx injection. Onyx filled the pouch and retrogradely reached some arterial feeders, achieving complete occlusion. Bleeding episode ceased and at 6 months follow-up no recurrence was found. Maxillary AVMs can be successfully treated by transvenous Onyx embolization.