Aim: To compare and evaluate the penetrability of three different root canal sealers – An Invitro study. Materials and Methods: Eighty freshly extracted mandibular premolars were used in the present study. The teeth were decoronated and canal lengths were established 1 mm short of the apex and divided into 4 groups. Group 1 used epoxy resin based sealer, Group 2 used polydimethylsiloxane based sealer, Group 3 used calcium based sealer and Group 4 used zinc oxide based sealer (control). The canal system was prepared using the protaper universal rotary system. Smear layer was removed by irrigating the canals with 3 ml of freshly prepared 17% EDTA solution, followed by irrigation with 3 ml of 5.25% NaOCl, for 3 minutes. EDTA was employed as the final rinse followed by a rinse with distilled water. Roots were sectioned using diamond disc, these sections were gold sputtered and examined under scanning electron microscope. Dentin sections were fixed in acrylic resin block, polyethylene tubes were cut to form 3-mm-high cylinders. The sealers were mixed according to the manufactures instructions and dispersed into the cylindrical space. The samples were then engaged perpendicularly at their base of universal testing machine at a cross head speed of 1 mm min-1. Results: It was found that Group 1 had higher depth of sealer penetration than the other group of sealers evaluated in the study. Conclusion: Calcium silicate sealer had comparable penetrability to that of epoxy resin sealer. Within the limitations of the present study it can be concluded that epoxy resin based sealer had better penetration when compared to that of other sealers evaluated in this study.