Because the incidence of venous thromboembolism, coronary heart disease, and stroke is increased in users of oral contraceptives (OCs), the possible causal metabolic side effects of OCs have been widely investigated. In this article we present epidemiologic data associated with OC use. Total plasma triglycerides and cholesterol levels were elevated in OC users while high-density lipoprotein cholesterol levels were lowered. Another section discusses some hormone-dependent physiologic and pathophysiologic aspects of lipid metabolism. Finally, we report on the isolated influence of estrogens and progestogens and their interrelation, including some recent findings about the effects of different progestogens on lipoproteins.