Purpose: to assess the dynamics of changes in salivary melatonin and the correlation with carbohydrate metabolism disorders in patients with type 2 diabetes mellitus (DM) during the war in Ukraine compared to the pre-war status. Object and research methods. From 2021 to 2024 participants from different regions of Ukraine were distributed depending on carbohydrate metabolism disorders and melatonin concentration in saliva. Examination for melatonin in saliva and HbA1c was carried out for 1 day in each patient: a saliva sample was collected at night (2.00–3.00), in the morning, fasting patients donated blood for HbA1c. Laboratory assessment of the level of melatonin in saliva was carried out by solid-phase enzyme-linked immunosorbent assay. HbA1c was determined by high-performance liquid chromatography. Results. According to the results obtained, the factor of chronic war stress is a statistically significant factor for changing the structure of HbA1c results on the background of melatonin deficiency. The part of results defining the type 2 DM group increases by Δ=+15.8%, for the prediabetes group — by Δ=+13.2%. Conclusion. The relative risk of type 2 DM and prediabetes in the presence of melatonin deficiency and the stress factor of war increases by 2.4 times.