The aim of this study was to evaluate and compare the sealing ability to obturate oval canals with three thermoplasticizedguttaperchaobturation techniques taking lateral condensation technique as the control. Ninety-five freshly extracted teeth were decoronated at 2mm coronal to CEJ. Biomechanical preparation was done using step back technique. The teeth were divided into three experimental groups of 30 teeth each and one control group of 5 teeth. The group I (control group) was obturated with lateral condensation technique, group II obturated with injectable thermoplasticizedguttapercha technique, group III obturated with thermoplasticizedguttapercha with downpack and backfill technique andgroup IV obturated with core carrier thermoplasticizedguttapercha technique. The sealability of each technique was assessed by a dye penetration method. The roots were given two full layers of nail polish varnish except apical 2mm. Specimens were then immersed in India ink for 48 hours. Robertson's technique was used to clear the specimens. The linear dye penetration was measured from anatomic apex to the deepest extent of dye penetration in a coronal direction using triocular stereomicroscope at 10 x magnification. The mean dye leakage of group I was 2.6700mm;group II 0.1713mm;group III 3.3977mm; group IV 2.3210mm. When the means of all the four groups were compared using Kruskal Wallis test the difference was found to be very highly significant with the value<.001**, meaning there by that group II is significantly better than the other three groups as far as sealing ability is concerned.