Enhancing the thermal conductivity of polymer materials is actively being attempted by applying metal/carbon-based micro-inanoparticles with higher thermal conductivity. In this study, a generalized correlation for predicting the thermal conductivity of composite materials is proposed based on an extensive FEM numerical study. The effects on the effective thermal conductivity of composite materials were investigated in regard to the thermal conductivity ratio between a particle and the matrix material, the particle volume fraction, and the thermal contact resistance between the particle surface and the matrix. The results indicate that the effective thermal conductivity increases with either the particle volume fraction or the conductivity ratio in general. This trend changes when the thermal contact resistance is present and greater than a threshold value. Based on the results, a generalized correlation, is proposed as a function of the three aforementioned non-dimensional parameters. The results cover wide ranges of the parameters and can be widely utilized for predicting the thermal conductivity of composite materials. (C) 2014 Elsevier Ltd. All rights reserved.