The author reports the clinical and laboratory findings in 102 patients of hepatolenticular degeneration (HLD) followed up in the Department of Neurology, University of São Paulo Medical School, since 1946. The problem of the early diagnosis of the relatives is analysed, the pathology of Wilson's disease is reviewed, and the relationship of HLD with other hepatocerebral diseases is examined. Etiopathogenesis is discussed according to current researches, the role of the decreased biliary copper excretion being emphasized. The results of treatment with D-penicillamine in 84 cases are commented.