Polymer nanocomposite samples were prepared by mechanical mixing of novolac epoxy polymer (EEW 180 g/eq) and varying concentrations of nano CaCO3 (0-5 wt%) for 30 min. using an electrical stirrer of 4000 rpm followed by uniform mixing of curing agent triethylenetetramine (TETA). The prepared mixtures were poured into a Teflon mold, designed as per ASTM standard. Thereafter subjected to cure at 110 °C for 1hr and post-cure at 70 °C for 5 hrs. The prepared nanocomposite samples were investigated for flexural strength, flexural modulus, impact strength, toughness, elongation at break, elastic modulus and hardness Shore D. It was observed that the sample containing 4 wt% nano CaCO3 showed the maximum value of flexural strength, flexural modulus, impact strength, toughness, elongation at break, elastic modulus and hardness Shore D, compared to the neat epoxy matrix. The curing reaction of nanocomposite samples was confirmed by FTIR spectroscopy and the morphological properties were investigated by SEM.