Harmful influence of tobacco smoke on mother and child comprises many effects, among which the best known are: impaired fecundability, increased risk of pregnancy and perinatal period complications, increased morbidity of neonates and respiratory, circulatory and neurological disorders in neonates, infants and older children. The aim of this study was to assess smoking prevalence among pregnant women and young mothers and to assess the degree of exposition of infants to environmental tobacco smoke (ETS). The study was carried out among 74 women after delivery in the F. Raszeja City Hospital in Poznan, Poland, between December 2005 and May 2006. Smoking prevalence among pregnant women was 8.1% (women with high educational level--2.6%, others--14.3%). Smoking prevalence among mothers within the first year after delivery was 4.05% (women with high educational level--0%, others--8.6%). 17.6% infants (10.3% children of mothers with high educational level and 25.7% children delivered by the other mothers) were exposed to ETS because of smokers at home (other than mother); 10 infants exposed to ETS had non-smoking mother.