Abstarct: The aim of the study was to investigate the effect of blood flow restricted resistance training on serum hormone levels in relation to muscle size and strength in young men. A total of 30 healthy young men (aged 19-24 yrs) were volunteered for this study. Subjects were randomly assigned into three groups: a low intensity blood flow restricted resistance exercise (BFR) group (20% of 1-RM, 3 sets 15 reps), a traditional high intensity resistance exercise without blood flow restriction (HI) group (3 sets of 10 repetitions at 80% of 1-RM) and a control group. Both BFR and HI groups trained 3 days per week for 3 weeks for knee extension and squat exercises. Fasting serum cortisol, growth hormone (GH), IGf-1 and testosterone levels were measured in the morning pre and post exercise sessions. Data were analyzed with one-way ANOVA in the level of p< 0.05. After 3 weeks, serum GH, IGF-1 and cortisol levels changed significantly between three groups (P<0.05). However, there was no significant changes in serum testosterone between them (P˃0.05). In conclusion, short term BFR exercise training stimulated increases more than without BFR exercise training in anabolic-catabolic hormones in young men.