We examined the effect of tobacco smoking on the concentrations of leptin, soluble leptin receptor (sOB-R), total adiponectin, and free leptin index (FLI) in the serum of maternal-cord pairs. We also investigated the correlations between these biochemical parameters and newborn birth weight and length. The study included eighty-five healthy pregnant women, who were divided into smoking and tobacco- abstinent groups according to serum cotinine concentrations. We found that maternal and fetal leptin, sOB-R concentrations, and free leptin index were similar in smoking and tobacco abstinent groups. We observed significant negative relationship between the reported number of cigarettes smoked daily during pregnancy and cord blood leptin (r=-0.37; p<0.05). In the group of smoking women, total serum adiponectin concentrations were significantly lower than in the tobacco abstinent group in mothers as well as in cord blood (p<0.05). A significant negative association between the number of cigarettes smoked per day and total adiponectin concentration in maternal as well as newborn serum was observed (r=-0.38; p<0.05). Umbilical serum leptin, sOB-R, and FLI levels were significantly lower and adiponectin higher compared with maternal concentrations at birth (p<0.05). Mean birth weight and body length of the smoking mothers' infants were significantly lower (p<0.001; p=0.015, respectively) compared with the abstinent group, and negatively correlated with the daily number of cigarettes consumed (birth weight r=-0.39; p<0.05; birth length r=-0.37; p<0.05). Cord blood values of leptin, FLI and adiponectin were significantly correlated with newborn birth weight. We also observed a positive relationship between cord blood adiponectin levels and the birth body length in the two studied groups (r=0.49; p<0.002). Tobacco smoking during pregnancy decreases maternal and fetal serum adiponectin levels but does not have a significant effect on blood leptin concentrations. The direct association between the cord blood values of these adipokines and birth weight and length suggest that rather fetal (not maternal) adiponectin and leptin concentrations may be involved in fetal development during pregnancy.