Hiccup is caused by synchronous contractions of the diaphragmatic and intercostal muscles followed by the closure of the glottis. Intractable hiccup is defined as hiccup bouts lasting more than 48 hours or recurring despite various treatments. Recently we have experienced a case of postoperative intractable hiccup. We failed to stop intractable hiccup by pharmacological treatment, but succeeded by unilateral phrenic nerve block.