Background: High intensity interval training (HIIT) has been widely employed as an exercise protocol to reduce fat, and also in addition, interval recovery periods are the most important factors which can have great impact on weight loss. Therefore, the aim of this study was the evaluation of different recovery time between HIIT program on metabolic responses and weight loss in overweight women. Methods: Twenty-four overweight (BMI 29.5±3.5 kg/m2) volunteer women were randomly assigned into three groups (n=8/group) to study the effects of different recovery times: (group 1; HIIT with 60/60 activity-rest ratio (sec), group 2; HIIT with 60/30 activity-rest ratio (sec), and group 3 was set as a control. The participants performed 3 times per week 4 bouts/session (80% of Heart Rate Reserve). The exercise program gradually increased to 10 bouts/session. Results: The most important findings of this study were a change in the Body fat percentage (BF %) in the between group comparison: group1 (40.5±0.9), group 2 (41.2±0.7) and group 3 (41.1±1.1). Compared to the control group the 60/30 sec HIIT resulted in a significant decrease in BF % (p=0.002). However, no other significant differences in the body composition were found. Either there were no significant differences between the groups in T4, T3 and TSH, cortisol, HGH, FBS, blood insulin, insulin resistance insulin sensitivity or fatnessassociated hormones. Conclusions: In conclusion, considerable decrease in BF % in the 60/30 sec. rest interval group indicates that 30 sec recovery period in HIIT may reduce fat % more efficiently than 60 sec.