The presence of a new or persistent periapical radiolucency adjacent to a root-filled tooth is often used as a criterion of endodontic treatment "failure" that needs endodontic retreatment. Objectives: To study the effect of some factors to the periapical healing of endodontically retreated teeth. Methods: The data was collected from the treatment records, before and after endodontic retreated periapical films of 49 patients who received conventional endodontic retreatment. There were 86 roots from 54 teeth evaluated radiographically 4-5 years after retreatment. The periapical and root canal filling condition were registered and compared by two observers. Results: The results of periapical healing after endodontic retreatment 4-5 years showed complete healing 60.47%, improved healing 5.8%, unchanged healing 6.98% and deterioration 6.98%. The size of preoperative periapical lesion significantly related to the level of periapical healing (p<0.05). While the distance of root canal filling from apex and the density of root canal filling after endodontic retreatment did not significantly related to the level of periapical healing (p>0.05). Conclusion: From this study, it could be concluded that the factor which effect the healing was the size of the periapical lesion before retreatment.