Hypothermia is one of the most important factors having an influence on morbidity of the newborns. Physiology of neonatal thermoregulation and thermogenesis is described as well as range of methods used for preventing heat loss and maintaining neutral temperature. An article presents the main reasons of limited thermogenesis in prematures, ways of heat loss and consequences resulting from decreased or increased newborns temperature. Special attention was put on routine care of infants within delivery room, intensive care units, during neonatal transportation and on procedures necessary to avoid hypothermia or overheating of preterm infants.