Between 1984 and 1987 thirty European Centres reported 87 liver transplants (usually in combination with a renal transplant) in 80 patients with an underlying diagnosis of Primary Hyperoxaluria (PH1). Mean age of onset of first symptoms was 5.4+/-7.9 years with a mean delay to diagnosis of 4.2+/-6.3 years. The mean age at transplantation was 17.3+/-11.7 years with a mean duration of dialysis of 3.1+/-3.1 years. There was a family history in 43% of cases. Following transplantation one, two and five year patient survival rates were 88%, 80% and 72% and graft survival rates were 82%, 78% and 62% at the same time intervals. Patients who had been on dialysis for less than two years at the time of transplant were more likely to be assessed as being in good general condition at the time of transplantation and had better survival than those who had been on dialysis for longer time periods and carne to transplantation with evidence of marked systemic oxalosis. Combined liver/kidney transplantation appears to give excellent results in patients with PH1 although the results are poor when transplantation is delayed until advanced systemic oxalosis has developed. The registry will continue to collect and analyse data from patients undergoing liver/kidney grafting for PH1.