We report a patient who developed ulcerative colitis during the course of primary biliary cirrhosis (PBC). PBC was diagnosed by liver histology when the patient was 31 years old, at which time no symptoms were observed. At 45 years of age, the patient complained of bloody diarrhea and abdominal pain, and she was diagnosed with ulcerative colitis by colonoscopy and histological examination. The patient had HLA-DRB1(*)1502 and (*)0802, which are associated with both diseases. Ulcerative colitis should be considered in the differential diagnosis of bowel disease in patients with PBC. The possible genetic associations between 2 diseases are also discussed.