The purpose of this in vitro study was to evaluate the sealing ability of three sealers(Sealapex, Pulp canal sealer, AH26) used with continuous wave method using an anaerobic bacterial leakage model. 53 extracted human teeth with straight and single canals were prepared with crown-down pressureless technique using .04, .06 taper Profile(Maillefer, Swiss). Master apical file was maintained as #35 K-file. All canals of the experimental teeth were obturated with continuous wave method using System B(Analytic technology, U.S.A.) The teeth were randomly divided into three experimental groups of 15 and two control groups of 4. Experimental group 1 was obturated with Sealapex and group 2 with Pulp canal sealer, and group 3 with AH26. A dual chamber anaerobic bacterial leakage model was assembled. Brain heart infusion with yeast extract, hemin, menadion, and the chromogenic indicator bromocresol purple was used as the culture broth for Fusobacterium nucleatum(VPI 10197), The specimens were incubated in anaerobic chamber at $37^{circ}C$ and were observed every 2 to 3 clays, The coronal leakage was evaluated through the color change of culture broth in lower chamber for 60 days. The results were as follows: 1. The incidence of bacterial leakage in group 1 (Sealapex group was 80%, 53% in group 2 (Pulp canal sealer), 27% in group 3 (AH26). 2. There were statistically significant differences in leakage scores between group 1 and group 2, and between group 1 and group 3, respectively. (P<0.05) 3. There was no significantly difference in leakage score between group 2 and group 3. (P>0 05)