Abstract Background and Objective: Chronic kidney disease is a major health problem that is associated with low quality of life and premature death. According to the contradictory results of some studies regarding the effect of exercise and physical activity on renal indicators, this study was conducted to determine the relationship between physical activity and glomerular filtration rate (GFR) in the population of Fasa County, Fars province, Iran. Methods: The current cross-sectional study is derived from the data of the Fasa Persian cohort study. In order to measure the level of physical activity, a standard questionnaire was used in three levels of low, moderate and intense physical activity. Also, renal function was evaluated in three levels: normal, mild insufficiency, and severe insufficiency based on milliliters per minute. In addition to this, the demographic characteristics of people including age, gender, etc. were also evaluated. Findings: The number of studied people was 5963. The mean physical activity and GFR level in the studied subjects were 2540.1±703.9 (MET-min/Week) and 77.7±11.2 ml/min, respectively. Analytical evaluation showed that there was a statistically significant relationship between GFR levels and physical activity in all three levels (p< 0.001). Also, a statistically significant relationship was observed between GFR levels with the variables of age, gender, body mass index, waist circumference, blood sugar, blood pressure, sleep duration, smoking, diabetes and hypothyroidism (p< 0.001). Conclusion: The results of this study showed that there is a direct relationship between the levels of glomerular filtration rate (GFR) and physical activity.