The first description of Lesch-Nyhan disease was in 1964; the first two patients were seen in 1963. The disease has caught the imagination of a variety of clinicians and scientists. The clinical picture is striking, combining spasticity, involuntary movements, and cognitive retardation with self-injurious behavior and the manifestations of gout. Biochemically, the overproduction of uric acid--the end product of purine metabolism--was, when measured, the largest ever seen. The disease is now well understood on a molecular basis. Enzyme analysis and mutational analysis have made available a full range of genetic testing, including diagnosis, carrier detection, and prenatal diagnosis. Therapy with allopurinol has been effective for those manifestations the disease shares with gout. Treatment for the neurological and behavioral features of the disease remains elusive.