© 2015 Australian Society of Endodontology IncThe aim of this study was to compare the clinical and radiographical success of mineral trioxide aggregate (MTA) and gutta-percha/AH-Plus used as a root canal filling material in primary second molars without successors. A total of 16 patients (9 girls, 7 boys) aged 6–13 years (mean: 10.5) were selected and randomly distributed into the treatment groups. Children were recalled for clinical and radiographic examination at 6, 12, 18, 24 and 36 months. Differences in treatment outcomes were analysed using chi-squared and Fisher's exact tests. Clinically, there was no significant difference in the success rates between the groups at the end of a 3-year follow-up period (MTA: 100%; Gutta-percha/AH-Plus: 70%) (P > 0.05). However, radiographically, there was a significant difference between the groups (MTA: 80%; gutta-percha/AH-Plus: 30%) (P < 0.05). The present study showed that MTA can be recommended for use in root canal treatment of primary molars without successors based on better radiographic success.