Sudden infant death syndrome (SIDS) is an unexpected non-violent death of apparently healthy child aged 7 days to 1 year, in which the anamnesis and autopsy data do not allow to find out the cause of the fatal outcome. Researchers have not come to a consensus on the thanatological role of morphological changes in the brain. Aim. To determine pathomorphological changes in the brain in the case of sudden death syndrome in children. Material and methods. Forensic medical studies of 118 deaths of healthy children who died suddenly for the period 2008-2017 were carried out and analyzed on the territory of the Stavropol region. Autopsy material was divided into groups: the main group (1) consisted of 74 observations (62.8%), where SIDS was the main final sectional diagnosis. The comparison group (2) consisted of 44 (37.2%) observations; the children died suddenly at home as a result of viral-bacterial pneumonia. For control, the third group was formed (3), which included 45 observations, where the death of children occurred as a result of drowning and carbon monoxide poisoning. Results and its discussion. A histological examination of pieces of the brain in the case of sudden death syndrome revealed the foci of angiomatosis of the vessels of the pia mater and brain matter with the normal structure of the elastic membrane of the arteries, the effects of glial proliferation in the subependymal region of the lateral ventricles and subcortical formations. In the medulla oblongata, in a detailed study of the posterior (vegetative) nucleus of the vagus nerve, degenerative changes in neurons were detected in the form of chromatolysis and karyolysis, a glial reaction of the type of neuronophagy. Conclusion. Pathomorphological changes in the brain stem may be due to combined intrauterine hypoxic and intrapartum traumatic factors, which, potentiating each other, lead to dysregulation of the respiratory rhythm with the development of a fatal outcome during sleep.