The purpose of the present investigation was to study the effects of testosterone and anabolic steroids on serum lipids in power athletes. Altogether 11 national top-level adult athletes completed the study. Five of them volunteered for the study group and the rest for controls. The follow-up consisted of 9 months of a strength training period. During the first 6 months, the subjects in the study group self-administered androgenic steroids on an average of 57 +/- 24.9 mg/day. The most interesting observation was the extremely low high-density lipoprotein (HDL) and HDL2 cholesterol concentrations of the androgen users. After 8 weeks of training, the study group had significantly (P less than 0.05) lower HDL cholesterol concentrations than the control group (0.53 +/- 0.11 and 1.14 +/- 0.19 mmol/l, respectively). This difference remained significant from 8 to 32 weeks of training. No systematic changes were observed in the control group. The HDL2 cholesterol concentration decreased by about 80% (P less than 0.01) and HDL3 cholesterol by about 55% (P less than 0.01) from the onset values in the study group. A substantial decrease in HDL cholesterol to total cholesterol and in HDL2 cholesterol to HDL3 cholesterol ratios were also noticed under the influence of exogenous androgens. The results of this study suggest that the sustained use of testosterone and anabolic steroids have a marked unfavorable effect on the pattern of HDL cholesterol in the serum of male power athletes.