OBJECTIVE To determine whether cigarette smoking, as a risk factor for CAD, affects (anti)oxidant status. METHODS The study included patients with CAD, divided according to their smoking status and the number of cigarettes smoked during a day. Biological markers of oxidative stress (concentration of oxidants and activity of antioxidant enzymes) were measured in all subjects. RESULTS The study included 300 patients with CAD, (average age of 63 ± 11 years), predominantly males. Of the total, 34.0% were active smokers, 23.0% were former smokers, and 43.0% were non-smokers. Most of the active smokers smoked 1-20 cigarettes/day. In terms of concentration of oxidants (MDA and HP) there was not a significant difference between smokers versus non-smokers. As for the activity of antioxidant enzymes (SOD, CAT and GPX), a statistically significant difference was found in the activity of GPX among the active smokers with CAD and the non-smokers with CAD (p = 0.039). CONCLUSIONS Smoking as a risk factor for CAD is closely associated with increased oxidative stress, and the number of cigarettes smoked plays an important role in increasing the level of oxidative damage and reducing antioxidant defence.