Various brands of thermoplastic gutta-percha (GP) obturation materials are on the market, and knowledge of their thermal behaviors is of a great interest to clinicians using warm GP technique. In this study, the thermal properties of eleven commercial brands of GP materials were investigated by differential scanning calorimetery (DSC) and thermogravimetric analysis (TGA). The relationship of the thermal properties of the tested materials to their resistance forces against the trigger squeezing action was also evaluated. From the DSC analysis results, all products demonstrated thermal behaviors of typical beta-phase gutta-percha showing major endothermic peaks at 48-50℃ and 53-61℃ exhibiting beta- to alpha- crystalline transformations and alpha- to amorphous transformation, respectively. The TGA data indicated that remaining weights of B&L-H, Dia-H and Sure-H products after heating up to 600℃ were higher than those of their soft type products, B&L-S, Dia-S, and Sure-S materials, respectively. The remaining weights and resistance force to trigger squeezing action of the tested materials were well corresponded with the viscosity-types designated by the suppliers.