Intensity of oxidative stress caused by prooxidant-antioxidant imbalance may have a pathophysiological effect in fetus of women smoking during pregnancy. Uric acid is the main contributor (60%) to TRAP (total radical trapping antioxidant parameters) which is markers of the plasma total antioxidants capacity. Therefore the aim of the study was to estimate the effect of tobacco smoking on concentration of uric acid in blood of pregnant women and in umbilical cord blood. Correlations between uric acid and total plasma antioxidant capacity in mothers and their babies were also studied. Healthy, pregnant women (n=147) were divided into groups non-smoking and smoking according to questionnaire declaration and concentration of cotinine in serum and urine. Concentration of uric acid in plasma was measured by enzymatic method using available kits from bioMERIEUX (France). We observed that, in both of studied group plasma concentration of uric acid increased during pregnancy. In group of smoking women level of uric acid was lower by 20% in I, by 25% in II and by 15% in III trimester than in group of tobacco abstinent. The differences were statistically significant, although the range concentrations in individual patients in both studied groups were similar (from 102.0 micromol/l to 408.0 micromol/l). In umbilical cord blood of children of smoking mothers mean level of uric acid was lover by 18% than in control group. Plasma concentration of uric acid was significantly correlated with total plasma antioxidant capacity both in smoking (r=0.75; p<0.001) and tobacco abstinent (r=0.60; p<0.05) pregnant women. The similar correlation was observed in umbilical cord blood in both groups (smoking: r=0.74; p<0.001, non-smoking: r=0.60; p<0.05). Reduced concentration of uric acid in plasma of women smoking tobacco during pregnancy suggest, that utilization of this antioxidant for neutralization of free radical present in cigarette smoking is enhanced and may have a negative effect on total plasma antioxidant capacity in mothers and their babies.