Ascariasis is the most common helminthic infection in developing countries. It may cause chronic abdominal pain, tenderness and bloating. Our aim is to report a case of acute episodic abdominal pain and pancreatitis associated with ascariasis. We report a 59-year-old female patient who was admitted for acute abdominal pain, having had several previous similar events before one of them was diagnosed as acute idiopathic pancreatitis. On admission, her physical exam was normal. Laboratory results showed hemoglobin 12.2 g/dL, white blood cell count 11 900 cells/mm3, eosinophils 420 cells/mm3, serum amylase 84 IU/mL, lipase 22 IU/mL and normal liver function tests. Abdominal ultrasound and a plain abdominal X-ray were also normal. An upper endoscopy showed round white worms in the duodenum and the stomach, some of them with bile in their intestines. The intestinal parasites were diagnosed as Ascaris lumbricoides, and the patient was started on albendazole, with full recovery within a week. We believe that ascariasis should be considered in patients with recurrent abdominal pain and idiopathic pancreatitis. © 2010 Japan Gastroenterological Endoscopy Society.