The serum concentrations of testosterone, androstenedione, estradiol and total low polar estrogens, mainly estradiol and estrone, were measured in 26 healthy male subjects. The subjects were divided into 2 groups, each of them with low (< 1.04 mmol/l) and high (> 1.56 mmol/l) levels of serum HDL [high density lipoproteins] cholesterol. The group with high HDL cholesterol had significantly higher testosterone than the other group. Positive correlations were established between HDL cholesterol and testosterone and total cholesterol and testosterone concentration in serum. [A possible relation between sex hormones and coronary risk factors is of interest for several reasons.].