Poly(vinylidene fluoride), PVDF, based hybrid nanocomposites (micro-CaCO3 + Montmorillonite (mmt)) containing various amounts of CaCO3 (30-40 parts wt.) were developed via co-rotating twin-screw extrusion and subjected to uniaxial stretching. A systematic study was performed to investigate the effect of micro-CaCO3 content and subsequent uniaxial stretching at various draw ratios (R = 4-5) on the mechanical, dielectric, electrical and piezoelectric properties of hybrid nanocomposites. For the as-extruded hybrid nanocomposites (without post-extrusion stretching), both dielectric properties and DC volume resistivity were significantly improved, probably due to the enhanced charge trapping capability of mmt in the presence of CaCO3 micro-filler. Similarly, hybrid nanocomposites containing 40 parts of CaCO3 and 3 parts of mmt presented a maximum piezoelectric coefficient, d33, of 7.4 pC/N. For stretched nanocomposites, the volume resistivity and dielectric properties of hybrid nanocomposites containing 40 parts of CaCO3 and 3 parts of mmt decreased gradually with increasing R possibly due to its porous structure as observed by SEM. However, stretched hybrid nanocomposites consistently exhibited enhanced piezoelectricity where a highest d33 value of 30.6 pC/N at R = 5 was obtained, which is attributed to the almost 100%  phase content and dipolar orientation induced by stretching and subsequent poling.