The case of a 74-year-old female patient who underwent a right hepatic lobectomy for hepatocellular carcinoma (HCC) which developed in primary biliary cirrhosis (PBC) is reported herein. During a follow-up examination for Parkinson's disease, an elevation of hepatobiliary tract-related enzymes and alpha-fetoprotein was uncovered. Diagnostic imagings showed a hypervascular, solitary, and encapsulated tumor measuring about 7 cm in diameter located mainly in the posterior segment. Positive antimitochondrial and antinuclear antibodies and a preoperative liver biopsy strongly suggested well differentiated HCC developed in PBC (Scheuer's classification stage II). Since the natural prognosis of PBC estimated by the Mayo risk score was fairly good and the liver function indicated sufficient tolerance for major hepatic resection, and preoperative computed tomography (CT) volumetry showed the atrophy of the right hepatic lobe, a right hepatic lobectomy was performed. A pathological examination revealed well encapsulated, moderately differentiated HCC with, in part, well-differentiated HCC in the tumor and stage II PBC in the noncancerous region. CT volumetry performed at postoperative day 14 showed a 146% enlargement of the remnant liver. An early detection of HCC and PBC by strict screening would prevent a limitation of surgical therapy due to a deteriorated liver function.