We report a case of bile duct cancer associated with anogenital Paget's disease. The patient was a 80-yr-old Japanese woman whose chief complaint was exanthema from the left vulva to the anus for the previous 4 yr. Histological examination of the skin biopsy of the vulva showed numerous Paget's cells. Resection of the lesion and the rectum were performed, and a permanent colostomy was created. More than 1 month after the operation, the patient suddenly developed obstructive jaundice. Percutaneous transhepatic cholangiography performed simultaneously with endoscopic retrograde cholangiography showed complete obstruction of the middle part of the bile duct. Bile cytology was class V. On the basis of these results, bile duct cancer associated with extramammary Paget's disease (EMPD) was diagnosed. About 5 months after the operation, the patient died of liver failure. Microscopically the tumor in the bile duct was poorly differentiated adenocarcinoma. Although EMPD has a tendency to be associated with underlying internal malignancies, this is the first reported case, to our knowledge, of bile duct cancer associated with EMPD.