The purpose of this study was to introduce a new method for quantitative testing of endodontic leakage. Study design. Eighty straight maxillary anterior teeth were divided randomly into 3 experimental groups of 20 samples each and 2 control groups. The experimental groups were prepared using the modified double-flared technique and obturated by lateral compaction of cold gutta-percha with Pulp Canal Sealer EWT, Sealapex, or AH Plus sealer. With the leakage test device, coronal 1mol/L glucose solution was forced under a hydrostatic pressure of 1.5 kPa toward the apical part of the root. Leakage was measured by the concentration of leaked glucose in apical reservoir at 1, 2, 4, 7, 10, 15, 20, and 30 days with the enzymatic glucose oxidase method. Results. No significant difference of sealing ability was found among 3 test groups at 1, 2, 4, and 7 days. From the tenth day, Pulp Canal Sealer EWT showed the highest leakage, and the leakage was not significantly different between Sealapex and AH Plus. Conclusions. The quantitative method is sensitive, nondestructive, and clinically relevant. Pulp Canal Sealer EWT showed more leakage than Sealapex and AH Plus in most observation time.