We report our single-center experience in treating 101 type II endoleaks with ethylene-vinyl-alcohol copolymer (EVOH, Onyx). In all, 65 endoleaks were embolized transarterially, and 36 were treated through a translumbar approach. Since the first transarterial embolization, when we began attempts to treat all patients initially via common femoral access, 58 (65.9%) of 88 patients were successfully embolized transarterially. All endoleaks in the translumbar group were successfully treated. At a median follow-up length of 15 weeks, a decrease or stabilization in aneurysm size was observed in 39 (73.6%) of the 53 endoleaks that had adequate follow-up computed tomography imaging. The overall residual endoleak rate was 34.0%. There was no difference in efficacy when comparing transarterial and translumbar approaches. We demonstrate that in most cases, transarterial access of the endoleak nidus is feasible, and controlled embolization is possible using EVOH. Furthermore, EVOH appears effective in long-term stabilization of aneurysm size and in preventing residual endoleaks.