A 62-year-old woman underwent aortic valve replacement for aortic stenosis. Her hemodynamics deteriorated with ST-T depression 6 hours postoperatively. Emergency coronary catheterization showed diffuse right coronary artery spasm. The spasm persisted despite intracoronary infusion of nitrates and calcium antagonists. Intracoronary adenosine triphosphate infusion finally resolved the spasm and stabilized the cardiac function.