The goal of this study consists of examining the mixing effect of thermokinetic mixing and melt extrusion methods on structural characteristics of the linear low density polyethylene (LLDPE) and its uncoated/coated calcium carbonate (CaCO3) filled composites. The influence of mixing power of both methods on morphological and thermal properties of the LLDPE/CaCO3 composites was investigated. According to the results, it was revealed that the LLDPE/CaCO3 composites processed by melt extrusion contained more CaCO3 particles in comparison to the composites obtained by thermokinetic mixer. In addition, the melt extrusion method delivered a more homogeneous distribution of calcium carbonate particles within the matrix polymer. Incorporation of uncoated/coated calcium carbonate affected the thermal behavior of the composites to a large extent. And, more severe changes were observed on the composites generated on the thermokinetic mixer.