Purpose: The aim of this in vitro study was to evaluate the microleakage of premixed BioCeramics (BCs) and mineral trioxide aggregate (MTA) for sealing primary molar furcal perforations. Materials and Methods: This study was carried out on 30 extracted mandibular primary molars. Perforations of the furcation areas were created in the pulp chamber floor of the teeth. The molars were then divided randomly in two groups (n=15). Perforations were then repaired with biocompatible materials. After 72 h, the teeth were immersed in 2% basic fuchsine dye solution for 24h. The teeth were then sectioned longitudinally and evaluated for dye leakage. Data analyzed statistically using ANOVA test. Results: There was a statistically significant difference between the microleakage of MTA (1669.25±140.59 μm) and premixed Bioceramics(1275.21±235.998 μm) groups (P>0.008). Conclusion: Premixed Bioceramics appeared to have superiorsealing ability than MTA in perforation repair in primary teeth.