A 53-year-old housewife was the donor when living-related donor liver transplantation (LRLT) was performed in her younger sister (49-year-old) with terminal primary biliary cirrhosis (PBC). The donor's liver histology was diagnostic and compatible with PBC, although she was negative for antimitochondrial antibody (AMA: a specific marker of PBC) by immunofluorescence and had normal liver function tests as well as no symptoms of liver disease. In this patient with latent PBC, AMA was eventually detected by immunoblotting, although it was not detected by ELISA. These findings indicate that a family history of PBC is a risk factor for the development of this disease. Our patient was diagnosed before the advent of any clinical or biochemical indicators and before or at the onset of AMA positivity, so her liver histology revealed the earliest stage of PBC.