A study was conducted to investigate the contribution of physical fitness evaluated by speed at onset of blood lactate accumulation (OBLA-SP), sex hormones and sex hormone-binding globulin (SHBG) on high-density lipoprotein cholesterol (HDL-c) in 12 young male endurance athletes. These athletes has a higher level and wide range of intraindividual variance (44 to 93 mg/dl) for HDL-c. The serum estradiol level was significantly and positively correlated with the level of apoprotein AI (Apo AI), and serum testosterone level was significantly and positively associated with the levels of both HDL3-c and apoprotein All (Apo All) . The SHBG level was positively associated with the levels of both HDL-c and HDL2-c. Age, certain anthropometric parameters such as percentage body fat, body mass index, and body fat distribution evaluated by waist to hip ratio, and physical fitness levels were not associated with HDL-c and other lipids and apoproteins. These results suggest that the HDL-c level in endurance athletes is strongly associated with not only male but also female hormones, and SHBG, being independent of age, body composition and physical fitnesss level.