Statement of Problem: When a tooth is treated endodontically, there are several objectives,which must be met for the root canal therapy to be successful. One of those objectives is the complete obturation of the root canal system.Purpose: The purpose of this study was to evaluate the apical sealability of the Theramfil endodontic obturation technique and compared it with lateral condensation.Materials and Methods: Thirty human maxillary permanent anterior teeth were similarly prepared. Following instrumentation, the roots randomly divided into two experimental groups of ten and two control groups (positive and negative) of five each. Ten roots were obturated with Thermafil and ten with lateral condensation. All immersed in Indian ink, then cleared and apical dye penetration was evaluated.Results: Average leakage values were minimum of 1mm to maximum of 2.9mm for lateral condensation and minimum 2mm to maximum 6mm for Thermafil group. There was statistically significant difference between Lateral Condensation and Thermafil obturation techniques (P<0.05).Conclusion: The results of this study indicate that root canals treated by lateral condensation technique leak less than Thermafil ones.