Primary hyperoxaluria is a recessive hereditary disturbance of glyoxylate metabolism caused by deficiency of the liver enzyme, alanine glyoxylate transaminase. The main symptoms are recurrent renal stones, nephrocalcinosis and renal failure. In the advanced state, the disease is frequently complicated by osseous disease, vascular insufficiency and cardiac arrhytmias caused by deposits of calcium oxalate in the tissue. The prognosis is poor. No specific medical treatment exists. Dialysis is not effective and the results of renal transplantation is poor. Combined liver and renal transplantation correct the metabolic defect and the excretion of oxalate is normalised. Combined transplantation must be regarded as the optimal treatment of renal failure caused by PHO. The transplantation should be undertaken preferably before the creatinine clearance falls below 10-20 ml/min in order to avoid tissue deposits of calcium oxalate and excessive urinary excretion of oxalate during immediate post-transplantation period.