Abstarct: The purpose of this study was to investigate the effect of menopause on fat oxidation response to acute exhaustive aerobic exercise. Therefore, 14 premenopausal women with range of age 18-29 years and 9 postmenopausal women with range of age 50-71 years, performed the incremental exercise test to exhaustion on a treadmill [adapted from a previous protocol (Achten J, Venables MC, and Jeukendrup AE. mextabolism 52: 747–752, 2003)]. fat oxidation was determined using indirect calorimetry by Respiratory gas analysis system. For each individual, maximal fat oxidation (MFO) and the intensity at which MFO occurred (Fatmax) were determined, and body composition were measured by body composition analyzer. Data were analyzed with variance analysis test with repetitive measurements, t-test and Pearson correlation test in the level of p< 0.05. Results of the current study showed that MFO (0.53±0.08 vs. 0.34±0.09 g/min) and Fatmax (70.91±10.45 vs. 54.51±11.32 %VO₂max) was significantly higher during running on treadmill in postmenopausal woman compared to premenopausal woman, respectively. While the impact of menopause on fat oxidation rate was 32%. Fat oxidation in women before menopause showed no significant association with body composition and body fat, particularly visceral fat in postmenopausal women showed a significant correlation with fat oxidation.