Galactosemia is an autosomal recessive disorder characterized by deficient activity of the enzyme galactose-1-phosphate uridyl transferase. Manifestations of the disease in infants include anorexia, vomiting, failure to thrive, lethargy, hypotonia, jaundice, hepatomegaly, and cataracts. These infants show hypoglycemia, susceptibility to Escherichia coli sepsis, hyperchloremic acidosis, albuminuria, and aminoaciduria. Definitive functional testing rests on erythrocyte transferase enzyme assay, with further characterization by electrophoretic mobility analyses and mutation identification. The early institution of a lactose-free diet in the neonatal period quickly resolves the neonatal manifestations. Independent of delay in diagnosis and dietary compliance hypergonadotropic hypogonadism, growth delay, verbal dyspraxia, and other speech disorders are reported in individuals with galactosemia.