A 45-year-old woman was referred to our department having suddenly developed, 9 months earlier, a pulsating mass on the right supraclavicular fossa and torticollis. Colour Doppler sonography and computed tomographic angiography showed the presence of an aneurysm (21 mm in diameter) of the suprascapular artery that had an anomalous origin from the subclavian artery. Thoracic outlet syndrome was excluded. After selective arteriography, the aneurysm of the suprascapular artery was successfully treated with ethylene-vinyl alcohol polymer (Onyx, MicroTherapeutics, Irvine, California, USA), a liquid embolic agent. The patient was discharged on the first postoperative day in good condition. Control colour Doppler sonography at 1 year confirmed the complete thrombosis of the aneurysm sac.