Thermal grease is generally used as a thermal interface material for improved conduction between a heat source and heat sink. Here, we report the enhancement of thermal conductivity of commercially available off-the-shelf thermal grease (thermal compound LS6006) used in cooling of electronic devices, by the addition of multiwalled carbon nanotubes (MWCNTs). The thermal conductivity of the MWCNT mats and MWCNT modified thermal grease was measured relative to the thermal conductivity of the grease, which was taken as the benchmark. The thermal conductivity improves and the optimum thermal management is observed for aligned MWCNT arrays glued through the thermal grease.