Primary hyperoxaluria is characterized by an increased urinary excretion of oxalate and the deposition of calcium oxalate crystals in the kidneys and other organs. This metabolic defect was thought initially to be a severe disease of infancy and childhood, characterized by recurrent nephrolithiasis and pyelonephritis and by a progressive course terminating in a uremic death. Studies by Newns and Black (1) in 1953 and by Aponte and Fetter (2) in 1954 demonstrated an increased urinary excretion of oxalate prior to death in such patients. Subsequently, the disease has been diagnosed with increasing frequency during life, and others (3-7) have confirmed