Methods using chemical vapor deposition (CVD) of diamond deposited on a sacrificial material provide CVD diamond microchannel structures and 3-D interconnection structures of CVD diamond microfluidic channels. The sacrificial material is patterned to define locations and dimensions of the microchannels. The patterned sacrificial material is selectively removed from underneath the chemical vapor deposited (CVD) diamond to form the CVD diamond microchannels. The CVD diamond microchannels are integrated with electronic structures to provide an integral microfluidic cooling system to electronic devices.