In the present study, we assessed the strongest determinants of plasma coenzyme Q10 (Qm10) in 518 men and women (aged 45-70 years) with a stepwise multivariate regression model. Male gender (P<0.001), serum cholesterol (P<0.001), serum gamma-glutamyltransferase (P<0.001), serum triglycerides (P< 0.001), age (P=0.017) and 4-day alcohol consumption (P=0.03) were the most important factors which were directly associated with plasma Q10). The intensity of conditioning exercise (P=0.03) and use of statins (P<0.05) showed an inverse association with plasma Q10. None of the assessed nutrients increased plasma Q10 levels significantly. Our results suggest that many confounding factors, in addition to serum cholesterol and triglycerides, should be taken into account when the role of plasma Q10 is examined in epidemiological research.