This paper represents a general method for the comparison of hydraulic and thermal performance of different heat exchangers designed for electronic coolant systems. As a case study, the performance of the High Flux Heat Exchanger, HFHE, developed by McDonnell Douglas, is presented. Performance equations for the hydraulic and thermal performance were developed for an applied heat flux as a function of coolant temperature and mass flow rate. In addition, the maximum heat flux capability for the HFHE was determined. The range of coolant temperature for this study was from-10 to 40 C, the range of mass flow rate was from 60 to 240 kg/hr, and the range of applied heat flux