This study aims at examine the effect of cigarettes smoking on paraoxonase 1 (PON1) activity and lipid profile. Our study included 102 smokers aged 35.5 +/- 16.0 years and 98 non-smokers aged 38.5 +/- 21.9 years. Total cholesterol (TC), triacylglycerols (TG), HDL cholesterol (CHDL) and LDL-cholesterol (cLDL) were determined by enzymatic colorimetric methods. ApoA1 and ApoB and Lp(a) were analyzed by immunoturbidimetry on Konélab 30, PON1 activity was measured by a kinetic method. Plasma CT, TG, cLDL, Lp(a) and ApoB/ApoA1 ratio appeared significantly higher in the smokers when compared to nonsmokers, since cHDL levels were lower. In addition, TG values were significantly higher in subjects smoking more than 30 cigarettes/day as compared to those smoking 5-10 cigarettes/day. We noted a significant decrease of PON1 activity in smokers compared to non smokers (94 +/- 104 vs 158 +/- 133 IU/L), with regression of PON1 activity according number of cigarettes/day. In conclusion, hypertriglyceridemia, low levels of cHDL, high levels of ApoB/ApoA1 and significant decrease of PON1 activity confirm the high risk of cardiovascular diseases in smokers.