a counter flow microchannel heat exchanger according to the present invention is shown in fig1 and generally designated at 20 the heat exchanger 20 comprises a housing 22 having a single layer of a plurality of parallel microchannels 24 as will be described below the heat exchanger 20 is designed such that a fluid coolant flows through adjacent alternating microchannels in opposite directions this counter flow configuration reduces the lateral temperature variation as compared to a unidirectional flow heat exchanger while maintaining low pressure drop and high coolant utilization the housing 22 of the heat exchanger 20 comprises two separate portions a base portion 26 and a surface portion 28 the surface portion 28 of the housing 22 has a plurality of slots which define the microchannels 24 the housing 22 shown in the figs is generally cylindrical a cylindrically shaped housing 22 represents a compact design and minimizes coolant flow thereby reducing power requirements for a liquid coolant pump however it is understood that the housing 22 of the heat exchanger 20 can be any shape including rectilinear opposed holes 30 are formed in the housing 22 of the heat exchanger 20 for receiving pins on the component to be cooled not shown.