A stronger positive association between fibrinogen or tissue-type plasminogen activator antigen (tPA-ag) and fasting insulin is observed in women than in men. We investigated whether this effect could be explained by a difference in smoking habits. The relations between markers for insulin resistance [fasting insulin and insulin resistance as estimated by the homeostasis model assessment (HOMA-IR)] and fibrinogen and tPA-ag were examined cross-sectionally in 4976 (582 for tPA-ag) subjects from the D.E.S.I.R. (Data from an Epidemiological Study on the Insulin Resistance syndrome) study. The modifying effect of smoking habits were evaluated. Seventeen percent of women and 27% of men were smokers. Fibrinogen concentrations were higher in smokers than in non-smokers, in men only. Female smokers had lower concentrations of tPA-ag than non-smokers. In both women and men, fibrinogen was positively associated with fasting insulin [women: beta = 0.33 mg/U (95% confidence interval: 0.29, 0.37); men: beta = 0.15 mg/U (0.11, 0.19)] and with HOMA-IR [women: beta = 0.17 microg/microU mol/l (0.15, 0.19): men: beta = 0.06 (0.04, 0.08)]. For tPA-ag these associations were for insulin beta = 0.76 mg/U (0.54, 0.98) and beta = 0.89 mg/U (0.67, 1.11), and for HOMA-IR beta = 0.47 microg/microU mol/l (0.33, 0.61) and beta = 0.45 microg/microU mol/l (0.33, 0.57), women and men respectively. The associations of fibrinogen and tPA-ag with insulin and HOMA-IR were sharply reduced in male smokers compared to male non-smokers, however the strength of the associations in male non-smokers did not reach that in women. Fibrinogen and tPA-ag are independently related with markers of insulin resistance, with the relation with fibrinogen being stronger in women than in men. The strong modifying effect of smoking habits does not completely explain this gender difference.