The thermal conductivity of the epoxy can be enhanced by incorporating conductive particles. These materials have potential to be used as heat sink in electronic devices. This paper presents the results of developing copper powder reinforced epoxy composite and measurement of their thermal conductivity. Epoxy composites containing 5, 10 and 15 wt copper particles were developed and the thermal conductivities were measured using the guarded comparative longitudinal heat flow technique. The thermal conductivity of 100 epoxy was found to be 0.204±0.018W/m-K and this value was 10 less compared to that of the theoretical value. The thermal conductivity measured for the epoxy composites containing 5 wt, 10 wt and 15 wt copper powder were 0.512±0.115, 2.094±0.080 and 2.432±0.210W/m-K, respectively. Scanning Electron Microscope (SEM) was used to examine the dispersion of copper particles in the epoxy. Poor dispersion of the conductive filler in the epoxy led to the formation of agglomerates resulting in reduced thermal conductivity of the epoxy composites. © 2010 American Institute of Physics.