Incarcerated obturator hernia is rare. One case is described which demonstrates many of the clinical features of the condition. Most affected are elderly women with chronic diseases, and the dominating symptoms are the same as for obstruction of the small bowel. The Howship-Romberg sign is said to be pathognomonic but is present in less than half of the cases. A correct preoperative diagnosis is rare. Resection of the small bowel is often necessary. The high mortality rate is due to the high age and often poor health of the patients, combined with late diagnosis.