Background and aims. Due to changes in criteria of diagnosis of GDM in Russia from 2013, it is relevant to study clinical course of GDM and pregnancy outcomes depending on terms and methods of diagnosis of GDM. Material and methods. 192 pregnant women aged 29.4±5.5 years, with a body weight 68.8±14.8 kg, BMI 25.3±5.3. 1st group: 86 pregnant women with high fasting glucose level before 20th week of pregnancy, 2nd group: 43 pregnant women with hyperglycemia in OGTT after 20th week of pregnancy, 3rd group: 63 pregnant women without GDM — control group. Results. Pregnant women with GDM were older than non-GDM women (29.5±5.4, 30.8±5.3, 28.4±5.7 years; р=0.05) and had higher body weight (72.3±16.9, 68.0±12.4, 64.4±11.5 kg; р=0.016). There weren’t difference in age, BMI between groups 1st and 2nd. The proportion of compliant women was the same in groups 1st and 2nd (38.4 and 34.9%; p=0.85). Pregnant women who needed insulin were older and had higher BMI (32.4±5.3 ys. vs 28.9±5.4 ys; р=0.04; 29.7±7,1 vs 25.6±5.7; р=0.03 respectively). The number of women treated by insulin was higher in 2nd group (46.6% vs 15.5%; p=0.03). Women, who treated by insulin, were younger and had higher BMI in 1st group compared with 2nd group (29.0±4.7 ys vs 35.0±4.3 ys; р=0.03; 34.4±5.7 vs 26.1±5.9 respectively; р=0.02). There was a significant difference in delivery term and summary severe adverse outcomes (macrosomia, preterm delivery, stillbirth) between non-compliant women with GDM and 3rd group (38.6±2.7 ws 1st group, 38.0±1.9 ws 2nd group, 39.5±1.09 ws 3rd group; р=0.008; 34.3% 1st group, 66.7% 2nd group, 19.4% 3rd group; р=0.027). The frequency of macrosomia and summary adverse pragnancy outcomes (hypoglicemia, neonatal jaundice, clavicle fracture, asphyxia) was higher in non-compliant women with GDM compared with compliant women (29.5% vs 12.2%; р=0.03; 70.5% vs 46.3%; р=0.02 respectively). Conclusions. Pregnant women with GDM diagnosed on base of high fasting glucose level, need insulin less frequently. Pregnancy outcomes in women with GDM depend on compliance rather than on terms or methods of diagnosis. Keywords Gestational diabetes mellitus, pregnancy.