Scimitar syndrome is a rare cause of left-to-right shunting. Surgery is indicated for a pulmonary-to-systemic blood flow ratio greater than 1.5:1 and not infrequently is complicated by postoperative obstruction. This report presents a case of scimitar syndrome and reviews how magnetic resonance imaging (MRI) can be used for initial and follow-up assessment of the syndrome with emphasis on suspected pulmonary venous obstruction. Given the potential high incidence of postoperative occlusion, MRI provides hemodynamic and anatomic information for both initial and follow-up assessment of scimitar syndrome. MRI clearly demonstrated transpleural pulmonary-to-systemic venous collaterals draining the obstructed scimitar vein.