Statins are recognized as the principal and most effective class of drugs for reducing serum cholesterol levels and, therefore, significantly reducing cardiovascular events and mortality. Statins may have a wide range of beneficial biological effects in addition to lipid lowering, a phenomenon commonly termed a 'pleiotropic effect'. However, the dose-dependency of these effects remains unclear. The present study evaluated whether atorvastatin, a potent statin, ameliorates the serum markers of pleiotropic effects, with a focus on dose-dependency. The pleiotropic effects of treatment with atorvastatin 5 mg/day and 10 mg/day for six months each in 15 patients with primary hypercholesterolemia were assessed in a prospective, randomized, open-label, crossover, single-centre study. Atorvastatin treatment dose-dependently decreased a serum marker of oxidative stress as well as the serum low-density lipoprotein cholesterol level. However, serum markers of inflammation and fibrinolysis decreased independently of dose. In conclusion, the dose-dependency of atorvastatin's pleiotropic effects differs among individual biological effects.