A fabrication of high performance heat sink composite material made of copper matrix reinforced by multiwalled carbon nanotubes (MWCNTs) up to 2.5 Vol. using powder injection molding technique (PIM) has been done successfully. A mixture of Cu/MWCNTs was compounded using a Z-blade mixer for homogenous dispersion of solids in the binder. The flow properties were measured using a capillary rheometer in the shear rate range which expected to occur during metal injection molding. To avoid binder degradation, TGA test was carried out. The TGA results showed that the processing temperature such as mixing and injection molding should be lower than 170C. The injection molding was carried out at low pressure. A combination of solvent and thermal debinding was used for binder removal from the samples and then the sintering process has taken place in argon gas at 900C. The results show that the sintered samples experience isotropic shrinkage around 21 with 14 weight loss and the density of the composites was decreased after sintering process. © 2011 IEEE.