In this article, thermal behavior of an epoxy based thermoset polymer has been discussed using atomistic molecular dynamics simulations. The simulations were performed on crosslinked network of EPON-862 and curing agent-W (DETDA) using consistent valence force field (CUFF). Thermal conductivity was calculated using both equilibrium as well as non-equilibrium molecular dynamics approaches and the results were found to be in good agreement with experimental findings. Different contributions of heat flux vector towards thermal conductivity and their possible coupling are discussed in terms of various convective and virial contributions. In addition, discussion of power spectra analysis of velocity autocorrelation function for crosslinked network shows a broad distribution of low frequency vibrational modes suggesting distribution of relaxation times. (C) 2009 Elsevier Ltd. All rights reserved.