In this paper, the heat transfer enhancement is experimentally investigated of a thermal management system (TMS) integrated with metal foam embedded in phase change material (PCM). The copper metal-foam is coated with a thin hard layer of high-temperature copper oxide (CuO) which is acting as a thermal conductivity enhancer (TCE). The metal- foam/PCM composite is attached to a heat sink and effect of various variables such as filling thickness ratio, volumetric fraction of PCM and number of input power levels are experimentally studied. The filling thickness ratios of metal- foam are varied from 0.0-1.0, RT-28HC as PCM of 0.0 and 1.0 volumetric fractions and heating powers are applied from 2 to 5 W. The melting and solidifying phenomenon of TMS is investigated with and without metal-foam and PCM at each input heating power. The results showed that metal- foam/PCM based heat sink can extract the base temperature during the heating period and heat transfer enhancement is improved monotonously with the increase of filling height ratio. The filling thickness ratio of 0.5 revealed the best thermal performance of PCM filled CuO coated metal-foam heat sink for passive cooling of portable electronic devices.