Obstructive sleep apnea (OSA) is a risk factor of hypertension, coronary artery disease and stroke. OSA is also considered a cause of accelerated atherogenesis. Advanced oxidation protein products (AOPP) are among the biochemical indicators of higher risk of atherogenesis as an independent risk factor for coronary artery disease. 20 men suffering from OSA were examined using night polygraphy, the AOPP were determined from their morning blood samples. The mean AOPP concentration in the patients group was 91.8 (SD=42.3) micromol/l, in the control group 76.2 (SD=35.3) pmol/l, the difference was not significant. The AOPP were found correlated with the AHI (apnoe/hypopnoe index) (R=0.485, P=0.030). The results support the hypothesis that OSA increases the oxidative stress and atherogenesis.