Menkes disease is an X-linked genetic disorder of copper transport that results in death from severe progressive neurodegeneration by the age of 3 years. We report here our 17 years' experience with the treatment of Menkes disease with subcutaneous administration of copper-histidine. Two patients (16 and 6 years of age) whose therapy was begun within 1 month of birth have done well neurologically. The other five patients have done poorly despite treatment initiated at 2 to 7 months of age. Copper-histidine therapy may be an effective treatment if started early.