Twenty-four top-level body builders [13 anabolic steroid users (A); 11 non-users (N)] and 11 performance-matched controls (C) were examined to determine the effect on lipids, lipoproteins and apolipoproteins of many years of body building with and without simultaneous intake of anabolic steroids and testosterone. After an overnight fast, triglycerides (TG), total cholesterol (TOTC), high density lipoprotein cholesterol (HDLC), low density lipoprotein cholesterol (LDLC), the HDLC subfractions HDL₂C and HDL₃C, as well as apolipoprotein A-I (Apo A-I), apolipoprotein A-II (Apo A-II) and apolipoprotein B (Apo B) were determined. Both A and N, compared to C, showed significantly lower HDLC and higher LDLC concentrations, with the differences between A and C clearly pronounced. In a subgroup of 6 body builders taking anabolic steroids at the time of the study, HDLC, HDL₂C, HDL₃C, Apo A-I and Apo A-II were all significantly lower and LDLC was significantly higher than in a second subgroup of 7 body builders who had discontinued their intake of anabolic steroids at least 4 weeks prior to the study. In some single cases HDLC was barely detectable (2–7 mg·dl⁻¹). The TG and TOTC remained unchanged. The present findings suggest that many years of body building among top-level athletes have no beneficial effect on lipoproteins and apolipoproteins. Simultaneous use of anabolic steroids results in part in extreme alterations in lipoproteins and apolipoproteins, representing an atherogenic profile. After discontinuing the use of anabolic steroids, the changes in lipid metabolism appear to be reversible.