Fat metabolism is important for judo in weight loss and recovery and for cycling in the energy production and recovery during workouts and competitions. Leptin controls the size of fat stores by inhibiting appetite. The purpose of this study was to compare serum leptin, lipoproteins and glucose levels between male national judoists and cyclists. The subjects of this study consist of totally 61 athletes, including 24 Turkish National junior judoists and 37 senior national cyclists. The mean age, training age and body mass index (BMI) of two groups are different from each other. Both judoists and cyclists were training before international competitons. Analyses of serum lipoproteins, triglycerides, total cholesterol, LDL-cholesterol and HDL-cholesterol, were determined by an automated chemistry analyzer kits. The differences between two groups was tested by Mann-Whitney U test and the correlations among parameters was obtained from Pearson Correlation formula. There were statistically significant differences in the mean age, training experience and BMI between judoists and cyclists statistical analyzes showed no significant difference among the means of total cholesterol, triglyceride, LDL and leptin between two groups. Significant differences were observed in the mean glucose, insulin and HDL values between judoists and cyclists. Significant difference was found only at 0.01 level in the mean of insulin and at 0.05 level in other parameters. Judoists had a higher insulin, total cholesterol, triglyceride and LDL levels than the cyclists, whereas cyclists had higher values than judoists In the mean of insulin, HDL and leptin. Cyclists also had lower insulin sensitivity than judoists. In conclusion, neither judo nor cycling had an effect on leptin, LDL, triglyceride, total cholesterol level. But glucose, insulin and HDL levels were changed depending on type of sports.