BACKGROUND The UK and Ireland Liver Transplant Audit collects information on all liver transplantations that are carried out in both countries. In this paper, we describe these transplantations and their outcomes in adult patients according to primary liver disease diagnosis, type of transplantation and period. METHODS A prospective cohort study of 7906 orthotopic liver transplantations carried out between April 1994 and June 2005 in the United Kingdom and Ireland. Multivariable logistic regression was used to investigate improvements in mortality according to period of transplantation adjusted for recipient and donor characteristics. RESULTS A total of 6,850 transplantations were done in adults (patients 16 years or older). Of these, 836 (12.2%) were first super-urgent procedures (33.7% men; median age 36 years), and 5,072 (74.0%) first elective procedures (60.0% men; median age 52 years). The percentage of patients who received a donor organ with abnormal appearance gradually increased, especially in patients receiving an elective transplant. Mortality at 90 days after first super-urgent transplant decreased from 29.6% (95% confidence interval: 23.5% to 36.9%) before October 1, 1996 to 16.0% (11.7% to 21.7%) after October 1, 2002. Considering the same time periods, mortality at 90 days after first elective transplant decreased from 10.6% (8.9% to 12.7%) to 7.7% (6.3% to 9.3%). Multivariable analysis demonstrated that these improvements cannot be explained by changes in the risk profile of recipients and donors. CONCLUSIONS Patients undergoing a liver transplantation in the most recent years had a better survival than patients with similar characteristics transplanted 10 years earlier. Posttransplant survival has improved despite a deteriorating quality of donor organs.