This study determine, in vitro, the coronal leakage of root canals evaluating the effect of smear layer removal by either EDTA or laser. Two sealers were also compared. Sixty- four canines were instrumented with the step-back technique and irrigated with 10 ml of 1% sodium hypochlorite. In Group 1, 10 teeth were sealed with Sealer 26 and 10 teeth were sealed with Grossman cement with no attempt of smear layer removal. Group 2 received a final irrigation of 15 ml of 15% ETA, and was sealed as in group 1. Group 3 received Er:YAG laser application (2940 nm, 140 mJ, 15 Hz and 42 J, 300 pulses, 500milli-sec pulse duration), and sealed as in group 1. Root canals sealed with Sealer 26 has significantly less coronal leakage than Grossman cement (p<0.05). Coronal leakage after smear layer removal with 15% EDTA or Er:YAG laser was not statistically different (p>0.01).