Twelve cases of juvenile Wilson's disease are reviewed. Eight presented with hepatic manifestations, and six of these showed a predominance of liver symptomatology throughout their entire illness. It appears that this type of onset is not uncommon when the disease begins in the pre-adolescent period. In childhood, chronic liver disease of unknown etiology should always be screened for Wilson's disease. Careful examination for Kayser-Fleischer rings should repeatedly be made. The finding of cupruria, aminoaciduria without glycosuria or albuminuria, and decreased blood uric acid levels are strongly suggestive of Wilson's disease. Punch biopsy of the liver with visualization of copper by means of an improved modification of the histo-chemical rubeanic acid method or Howell's newer histo-chemical method, or determination of copper content as well as histochemical analysis of liver obtained by surgical biopsy appear to be the only reliable methods at present for proof of diagnosis. [See Table III in Source Pdf.]