PURPOSE: To evaluate efficacy and safety of superior rectal artery embolization of hemorrhoidal disease as a first-line invasive treatment. MATERIALS AND METHODS: This prospective study was conducted between 2014 and 2015 on 25 consecutive patients (16 men and 9 women with a mean age of 53 y [range, 30-76 y]) with grade II-III hemorrhoids refractory to medical treatment. A transfemoral superselective superior rectal artery branch embolization was performed using 2- and 3-mm diameter microcoils. Over the following 12 months, clinical outcomes were evaluated using the French bleeding score, Goligher prolapse score, visual analog scale (VAS) score for pain, quality-of-life score. The primary endpoint was relief of symptoms by 12 months based on a 2-point minimum improvement on VAS score and bleeding score. RESULTS: At 12 months after embolization, clinical success was obtained in 18 patients (72%), 8 of whom had 2 embolizations. VAS score decreased from 4.6 to 2.3 (P < .01), and bleeding score decreased from 5.5 to 2.3 (P < .01). Quality-of-life and prolapse scores also showed improvement (P < .05), and no patients experienced any early or late complications. Complete clinical failure was observed in 7 patients. After coil embolization, the collateral supply to the hemorrhoidal cushions was significantly related to any recurrence (P = .001). CONCLUSIONS: Hemorrhoidal artery coil embolization was found to be a safe and effective treatment for grade II-III hemorrhoids.