Cigarette smoking is a global public health problem. According to the current estimations, more than one billion people worldwide smoke tobacco. The highest prevalence of smoking is observed in Europe and Central Asia. In Poland, nearly a half of males and 1/3 of females are smokers. Information concerning an increase in the prevalence of tobacco smoking among women is alarming. It is estimated that tobacco smoking is the cause of approximately 10% of deaths worldwide. If the present trend maintains itself, in the present 21^st century nearly one billion people will prematurely loose their lives due to tobacco smoking. Tobacco smoking by pregnant women additionally exerts a negative effect on the developing foetus. The objective of the study was analysis of haematological parameters of the erythropoietic system in pregnant women and their newborn babies after delivery according to the number of cigarettes smoked daily by the mothers in pregnancy. The studies were based on the questionnaire forms. The studies were carried out in all hospitals in Poland where pregnant women were hospitalized with their newborns on one day in 2010 and 2011. The material for the study were replies to the questions concerning the results of blood tests of mothers and newborns. No significant changes concerning haematological parameters of the erythropoietic system were observed in women after delivery. With respect to newborns, an increase was noted in the level of haemoglobin in the babies of women who, in the third trimester of pregnancy, smoked more than 6 cigarettes daily. The hematocrit value and amount of erythrocytes did not change. The results of the studies showed that tobacco smoking in pregnancy exerts a negative effect on the environment in which the foetus develops, and consequently, on the health of newborn babies.