In Poland, tobacco smoking by women in a procreational age as well as the pregnant women is a common phenomenon. The aim of the conducted research was to assess the usefulness of cotinine markers in different biological materials--mother and newborn's urine, cord blood se. rum, placenta--as a biomarker of tobacco smoking by delivering women, and dependence between these biomarkers and the newborn's health state. 218 pregnant women (117 smokers and 101 non-smokers), who were checked in at the Perinatology and Gynecology Clinic of the University of Medical Sciences in Poznan, took part in the first stage of the research (period between the twelfth and sixteenth week of pregnancy) carried out between years 2004-2006. In the second stage, 201 pairs of women (89 smokers and 112 non-smokers) and their newborns were checked after the women came to hospital to deliver. The research that was conducted showed that both cotinine in the urine of delivering women and in the urine of newborns as well as in the cord blood serum may be used as a biomarker of exposure of a foetus to tobacco smoke. For practical reasons, it must be assumed that the delivering women urine should be the material from choice. The research did not indicate the usefulness of the determination of cotinine in the placenta, in order to assess the exposure of the foetus to the components of tobacco smoke. On the other hand, again it confirmed the influence of tobacco smoking on the newborn's birth parameters, a correlation between the birth weight, body length and cotinine concentration in the urine of a mother makes it possible to predict the lowering of the antropometric parameters of the newborn as a result of tobacco smoking by pregnant women.