Abstract Sex hormones may play a role in the determination of cardiovascular disease. Recently lipoprotein(a) (Lp[a]) has been recognized as a risk factor for coronary heart disease. Estrogens and anabolic steroids have been reported to alter Lp(a) levels, yet no data are available on the association between in vivo concentrations of sex hormones and Lp(a) concentrations. We examined the possible associations of sex hormone-binding globulin, total and free testosterone, estradiol, and dehydroepiandrosterone sulfate to Lp(a) concentrations in men in two population-based studies (San Antonio Heart Study [n=178] and a Finnish study on the association between insulin resistance and atherosclerosis [n=87]). In neither study were sex hormones significantly related to Lp(a) concentrations. In addition, Lp(a) was significantly related to apolipoprotein(a) molecular weight (which was measured in the Finnish study only). These results were unchanged when Lp(a) concentrations were adjusted for apolipoprotein(a) molecular weight (a strong correlate of Lp[a] concentrations). We conclude that in vivo concentrations of sex hormones are unlikely to be associated with Lp(a) concentrations in men.