This paper reports three cases of malignant afferent loop obstruction after choledochojejunostomy. In the first case, a 75-year old woman, who had undergone left hepatectomy for bile duct cancer with bile duct resection, was admitted for Roux en Y reconstruction after choledochojejunostomy because of emesis. The local recurrent tumor caused occlusion of the duodenum and afferent limb, and bypass surgery was performed after transintestinal drainage. In the second case, a 57-year-old man, who had undergone pancreaticoduodenectomy for pancreas cancer, was hospitalized with a high-grade fever and epigastric pain. Exploratory laparotomy revealed widespread carcinomatosis causing afferent loop obstruction, and bypass surgery was performed. In the third case, a 60-year-old woman with paraaortic lymphnode recurrence of gallbladder cancer was admitted as she had afferent loop syndrome. Transintestinal drainage was performed. All these three patients were discharged. Bypass surgery for selective patients turned out to be an effective palliative treatment for malignant afferent loop obstruction.