The new methods that have been used to preserve pregnancy have reduced the frequency of premature birth. However, in this case, there is still a high mortality rate among neonates. Aim: The aim of the study was to assess the main causes of mortality in neonates with extremely low and low body weight. Results: The largest proportion of deaths among newborn babies with extremely low and low body weight was recorded during the gestation period of 25-26 weeks – 76.9%, at the gestation period of 27-28 weeks, deaths were 36.8%. The leading cause of death of premature newborns in the neonatal period is massive intracranial hemorrhages (45.5%). Intrauterine infection of various etiologies occupies three times the place of causes of mortality of premature newborns and occurs in 24.2%. Conclusion: Among newborns with extremely low and low body weight, mortality is present in every fifth case, the causes of which were: intracranial hemorrhages, intrauterine infection, respiratory distress with cider.