Background. Autogenous tooth transplantation is a reliable method for repairing missing teeth. Although it recently became a recognized and feasible treatment method in dentistry, the long-term efficacy of root canal therapy (RCT) has not been well confirmed. This study is aimed at determining whether RCT has a good effect on the success rate of teeth with complete roots in autogenous tooth transplantation. Materials and Methods. Data were collected from the Korea University Guro Hospital. Data of patients who underwent autogenous tooth transplantation within 9 years were collected. We selected 29 teeth with complete roots as the research subjects in our study. None of the patients had any systemic diseases. All cases in this study were obtained with patient permission. Results. According to the tooth vitality test, the autogenous teeth tested negative in dental pulp test and function. Nine of the 29 teeth with autogenous tooth transplantation were treated with RCT and survived throughout the observation period. However, 20 autogenous teeth were not treated with RCT, and eight of them did not survive. All statistical analyses were performed using IBM SPSS 20.0. The null hypothesis was rejected ( p < 0.05 ). Conclusion. For complete root teeth, the success rate after autogenous tooth transplantation after RCT is higher than that of teeth not treated with RCT.