A 47-year-old woman was referred to our hospital with recurring lower abdominal pain persisting for more than 2 weeks. Imaging modalities showed small bowel obstruction caused by a mass lesion in the terminal ileum. Despite undergoing fasting, rehydration, and decompression through an ileus tube, her symptoms persisted. Furthermore, the condition deteriorated on day 4, with the onset of her menstrual period. An emergency surgery was conducted on the 7th day after hospitalization. Surgical observations indicated severe stenosis around the ileocecal valve and ileal perforation approximately 40cm from the oral stricture. As a result, ileocecal resection was performed. Pathological examination revealed endometrial tissue infiltration through the mucosal lamina propria to the ileal subserosa. Thus, the patient was identified with intestinal endometriosis of the ileocecum. Endometriosis of the small bowel is an uncommon condition that eventually causes intractable bowel obstruction. Although preoperative diagnosis is considered challenging, intestinal endometriosis should be included in the differential diagnosis in cases of bowel obstruction in women of childbearing age.