While absolute power levels in microelectronic devices are relatively modest (a few tens to a few hundred watts), heat fluxes can be significant (~50 W/cm2 in current electronic chips; up to 2000 W/cm2 in semiconductor lasers). Microchannel diamond heat sinks created via microfabrication techniques make it possible to boost heat transfer rates well above what is possible with ordinary cooling devices. If nanodiamond particles are added in suspension to the circulating fluid in the microchannels, the heat carrying properties of the device would be increased even more. The devices we are proposing to fabricate would utilize diamond which has the highest thermal conductivity of any known material combined with a microchannel cooling system. These unique attributes would make microchannel diamond heat sinks prime contenders for the next generation heat sink. These devices could be utilized for efficient cooling in a variety of applications requiring high heat transfer capability including: semiconductor lasers, multichip modules in computers laser-diode arrays, radar systems, high-flux optics, etc. An added benefit for outer space applications is that besides having the highest known thermal conductivity, diamond is the best shielding material for micrometeorite protection.