Obturator foramen hernia is a relatively rare disease and is likely to occur in aged, thin females. Herein we report a case of obturator foramen hernia associated by incarcerated femoral hernia. A 95-year-old woman was seen at the hospital because of nausea and vomiting. At admission, she was diagnosed with incarcerated femoral hernia due to swelling at the right lower area of the groin. Because an abdominal simple X ray demonstrated intestinal obstruction as well as Howship-Romberg sign was obtained, a pelvic CT was performed. The pelvic CT demonstrated right obturator hernia. At laparotomy, a large omentum was incarcerated at the right femoral ring while the small intestine 130cm proximal from the terminalileum showed Richter type hernia at the right obturator foramen. Operative procedures included: reposition of the large omentum and the ileum; resection of a part of the large omentum; and closure of the hilus of the hernia. With a recent progression in imaging procedures, clinical cases diagnosed as obturator foramen hernia preoperatively have been increasing. Aggrssive examination sincluding CT scan are useful in making preoperative diagnosis of the disease, especially not to overlook associated hernia which is difficult to be detected by palpation like in this case.