Until December 1988, 38 patients with primary biliary cirrhosis (PBC) had been transplanted in the Nordic countries. The observed survival probability in accordance with Kaplan-Meier analysis was around 75% 2-3 months after surgery, with few deaths during the next 3 years. The observed survival curve was compared with the expected survival calculated from the experience of a recent English PBC transplant series; the patterns are very similar. Secondly, the observed survival was compared with the expected survival curve, calculated from the survival experience of an international trial of medical treatment-that is, the expected survival had the patients not been transplanted; after the first 2-3 months the observed survival stayed better than the expected survival. Finally, the merits of transplantation for each particular patient was evaluated by means of the ratio of probability of survival when transplanted to probability of survival when medically treated 3, 6. and 8 months after surgery. The ratio increased with time, indicating a relative increase in the benefit of transplantation with time after surgery.