Galactosemia is also a metabolic disease. Over the past decade, research has revealed hundreds of new hereditary metabolic disorders, and this group of diseases has become more diversified. Galactosemia is the second most common neonatal disease after phenylketonuria. Deficiency of galactose-1-phosphate-uridyltransferase is observed during the disease. The activity of galactose-1-phosphate-uridyltransferase in the erythrocytes of homozygous patients with galactosemia is not determined. In heterozygotes, the enzyme activity is 50% of normal activity. For the first time in the Republic of Azerbaijan, genetic screening of Galactosemia hereditary metabolic disease was carried out by immunoenzyme analysis in patients who applied to maternity hospitals and the Pediatric Research Institute in Baku, and glucose-6-phosphate dehydrogenase enzyme deficiency was detected in three newborns and two sick children.