Crohn’s disease is a kind of inflammatory bowel disease. Crohn’s disease involving exclusively th jejunum (jejunoileitis) is relatively rare. Because of lack of specific symptoms/signs and of various presentations, definitive diagnosis is difficult to make. Here, a 23 year-old male with such a disorder is presented. An initial impression of irritable bowel syndrome was made at our clinic and the tentative preoperative diagnosis was GI tract malignancy. Exploratory laparotomy and segmental resection of the diseased jejunum were performed. The patient had an uneventful hospital course, and was discharged on the 7th postoperative day. The possibility of jejunal Crohn’s disease should be kept in mind when the physician confronts a young patient suffering from watery diarrhea and body weight loss persisting for a period. Crohn’s disease is a chronic condition for which there is currently no curative treatment. Either medication or surgical intervention can alleviate symptoms and complications.