The authors analysed an incidence of performed exchange blood transfusions at the newborn babies ward prior to and after introduction of phototherapy into practice. This analysis included the causes of jaundice in newborn. The study included the causes of jaundice in newborn. The study involved 8,937 newborn babies delivered between 1981 and 1985. Prior to phototherapy (period between January, 1981 and July, 1980), 45 blood transfusions and 9 retransfusions were performed. During the period II (between July, 1983 and December, 1985), i.e. phototherapy, 30 blood transfusions and 1 retransfusion were effected despite of the higher number of delivered babies. The obtained results have shown favourable effect of the phototherapy in jaundice of perinatal period, especially in jaundice unconnected with blood Rh factor conflict and in premature babies. Phototherapy decreased the number of performed transfusions and retransfusions.