Sepsis is still one of the leading causes of child mortality worldwide, despite advances in its diagnosis and treatment. Difficulties in recognizing the transition of a localized infectious-inflammatory process to a generalized one lead to a belated diagnosis and the beginning of therapy. Meanwhile, the earlier treatment is started, the higher the patients’ chances of life. Early diagnosis of sepsis, which corresponds to modern ideas about this condition, is one of the main tasks for both scientists and practitioners. The aim of this review is to study modern recommendations for the diagnosis of sepsis and septic shock in children. The article reflects the epidemiology, etiological features, modern definitions and methods of diagnosis of pediatric sepsis.