Introduction: Endurance training increases capillary density in skeletal and heart muscles. But themolecular mechanism of these processes is not yet clear. Substantial evidence indicates that the vascularendothelial growth factor (VEGF, angiogenic factor) and endostatin (antiangiogenic factor) might play keyrole in this process. Therefore, we investigated the effect of endurance training on serum levels of VEFGand endostatin in wistar rat.Materials and Methods: The study was performed in 20 male wistar rats, which were aged between 64 ±6 days. All rats were subdivided into two groups randomly: endurance training group (n = 10) andsedentary group (n = 10). Therefore, the training group received 8 weeks of treadmill endurance training. Atthe end of endurance training program, the rats were anesthetized with halothane, and then blood samplewas drawn from the descending aorta for measurement of serum levels of VEGF and endostatin. Serumlevels of VEGF and endostatin was measured by ELISA method.Results: Results of the study showed that endurance training increased serum levels of VEGF anddecreased endostatin significantly. Furthermore, with adaptation to endurance training VEGF/endostatinratio increased significantly. Also, VEGF has not significant correlation with endostatin.Conclusion: These finding suggested that with adaptation to endurance training the balancebetween angiogenic and angiostatic factor switched to angiogenic factor. These finding mayprovide new insight into the mechanisms relating to capillary density increment in response ofendurance training.