The purpose of this study was to elucidate the morphometric changes occurring in hepatic lymphatics in primary biliary cirrhosis (PBC). The lymphatic vessels were stained intensely by enzyme-histochemistry for 5'-nucleotidase while blood vessels stained well for alkaline phosphatase (ALP). We performed a morphometric analysis to estimate the number of lymphatic and blood vessels and their areas, using computer graphics software (NIH Image). Both the number of lymphatics and their areas in specimens in patients with PBC at an early stage were found to have increased. Neither the number nor the areas of the blood vessels showed any obvious relationship with the degree of fibrosis of PBC. Our results clarified that the sizes and number of lymphatics are increased even in the early stage of PBC. This is thought to be due to increased lymph production, which is caused by disturbance of the microcirculation associated with portal hypertension.