Acase of chronic afferent loop syndrome treated by endoscopic balloon dilatation wasreported. A 80-year-old female was admitted to our hospital because of sudden onset ofepigastralgia accompanied by bilious vomiting.5hc had a past history of partial gastrectomy with reconstruction of Billoth II method. Narrowing of orifice at afferent loopwith the scar of ulcer has been demonstrated by follow up endoscapic examinations. Ulcerwas detected 3 years previously and treated with H2-hlocker. A diagnosis of chronicafferent loop syndrome was made from the finding of CT demonstrating a dilated afferentloop and endoscopie findings. Symptoms improved by endoscopic treatment with balloondilatator. No recurrence of symptoms has occurred since the endoscopic treatment vasperformed.