Introduction: Fetal loss syndrome is a multifactorial disease characterized by a universal integrated response of the female body to any ill health in the pregnant woman, the fetus and the environment, the result of the action of functionally weakened variants (alleles) of many genes against the background of adverse external and internal factors. Glutathione-S-transferase (GST) metabolizes foreign substances or controls the entry of carcinogens into cells. Aim: The goal of our research was to establish the role of the polymorphic variants of the xenobiotic enzymes genes GSTM1 and GSTT1 and IIe 105Val of the gene GSTP1 in the mechanism of formation and development of fetal loss syndrome. Material & Methods: Molecular genetic studies were conducted in 114 pregnant women aged from 20 to 45 years old. Molecular genetic examination of biomaterials (DNA) was performed at Department of Molecular Medicine and Cellular Technologies of the Research Institute of Hematology and Blood Transfusion of the Ministry of Health of the Republic of Uzbekistan. Statistical analysis of the results was carried out using the statistical software package “OpenEpi 2009, Version 2.3”.