Three inborn errors of galactose metabolism are known. The most important is classic galactosemia due to galactose-1-phosphate uridyltransferase (GALT) deficiency. A complete or near-complete deficiency is life threatening with multiorgan involvement and long-term complications [1]. Partial deficiency is usually, but not always, benign. Uridine diphosphate galactose 4-epimerase (GALE) deficiency exists in at least two forms. The very rare profound deficiency clinically resembles classical galactosemia. The more frequent partial deficiency is usually benign. Galactokinase (GALK) deficiency is extremely rare and the most insidious, since it results in the formation of nuclear cataracts without provoking symptoms of intolerance. The Fanconi- Bickel syndrome (Chap. 11) is a congenital disorder of galactose transport due to GLUT2 deficiency leading to hypergalactosemia. Other secondary causes of impaired liver handling of galactose in the neonatal period are congenital portosystemic shunting and multiple hepatic arteriovenous malformations.