Evaluations were made of emerging cooling technologies having potential to remove 100 W/sq. cm steady state heat dissipation while holding chip junction temperature to 90 °C. Several constraints were imposed on the cooler due to the intended application of cooling fighter aircraft electronics. Constraints included a practical lower limit on coolant supply temperature, the preference for a nontoxic, nonflammable, and nonfreezing coolant, the need to minimize weight and volume, and operation in an accelerating environment. Evaluation factors included aircraft system impact, cooler development status, reliability and maintainability, safety, etc. This paper describes the cooling concepts, and assessments made as to their relative performance in a fighter aircraft environment.