Introduction: Estrogen is the basis of pregnancy and is involved in many physiological activities. Regarding the effects of exercise on lipid profile and estrogen, the aim of this study was to investigate the relationship between estrogen and lipid levels in active women. Methods: From among female students of Islamic Azad University of Masjed-Soleiman, after examining the conditions of inclusion and signing consent form, 38 inactive women (age: 26.1 ± 6.27 y; BMI: 24.2 ± 2.4 kg.m-2) and 31 active women (at least 150 min activity per week; age: 27.68 ± 5.72y, BMI: 22.3 ± 65.64 kg.m-2) participated in study. In the late folicular phase, 3-cc blood was taken from the subjects in the fasting state. HDL, LDL, TG, cholesterol and estrogen (17 Beta-estradiol) were measured during four months. Pearson correlation and sample t-test for statistical analysis was used. The significance level was p <0.05. Results: The results showed in active women there was a significant inverse relationship between estrogen and cholesterol (P = 0.01) and TG (P = 0.02). Comparing the groups, the levels of cholesterol (P = 0.0001), LDL (P = 0.0001) and TG (P = 0.01) in active woman were significantly lower than inactive women. Conclusion: The results of our study showed that measurement of estrogen and blood lipids in different times of menstrual cycle was different in active and inactive women. Therefore, regarding the enormous effects of endogenous estrogen on health, it is recommended that women maintain a good level of activity per week in order to benefit from its health benefits. پرونده مقاله