Anisakiasis usually occurs in the stomach and can easily be diagnosed by digestive tract endoscopy as opposed to enteric anisakiasis which is very rare and difficult to be diagnosed definitively. The most important and useful tool in diagnosing enteric anisakiasis is obtaining an accurate patient history of having eaten raw fish before the onset of symptoms. We report a case of small bowel obstruction caused by acute invasive enteric anisakiasis. A 60-year-old woman visited the emergency room suffering from sudden abdominal pain. She had eaten raw fish 1 day before the onset of symptom. Radiologic studies showed small bowel obstruction. However, no definitive cause could be found. An emergency laparotomy revealed edematous and dilated proximal jejunum and a focal stenosis of the distal jejunum. Segmental resection of the jejunum was performed, and histopathological examination revealed enteric anisakiasis. The patient was discharged on the 7th day after surgery following an uneventful course of recovery. (Korean J Gastroenterol 2010;56:192-195)