Introduction: The aim of this experimental, cross-sectional study was to investigate the effect of one session of moderate and heavy resistance exercise on the acute and delayed responses of leptin, insulin, cortisol, testosterone and 24-hour energy expenditure in healthy men. Materials and Methods: Thirteen healthy men (age 37.5yr, body mass index 26.40kg/m2, body fat 22.46%) randomly participated in three exercise groups, the moderate resistance exercise (MR, 3 sets × 10 repetitions at 70 % 1 repetition maximum (1RM)), the heavy resistance exercise (HR, 3 sets × 10 repetitions at 80 % 1RM) and the controls(C). Blood samples were taken (after overnight fasting) before and immediately after exercise and after 4 and 9 hours of recovery. Serum leptin, insulin, cortisol and testosterone concentrations were measured using ELISA methods. Results: After adjusting for percentage changes of plasma volume, serum leptin reduced immediately after exercise and control sessions but returned to primary levels after 9 hours of recovery (p<0.05). Immediately after exercise and control sessions, serum cortisol and testosterone decreased and serum insulin increased. No significant change was seen in 24-hour energy expenditure after MR and HR protocols. Conclusion: To conclude there were no meaningful acute and delayed effects of moderate and heavy resistance exercise on serum leptin, insulin, cortisol, testosterone and 24- hours' energy expenditure in healthy men.