High temperature power electronics have become a vital aspect of future designs of compact power converters for applications including power conditioning and distributed motor/actuator controls. However, the development of high temperature capacitors lag far behind other system components (e.g. semiconductor switches and that can operate at temperature >200°C). The performance of these systems would benefit significantly from components and packaging designed and optimized for high temperature (200°C to 400°C) under generally harsh environmental conditions. In previous papers we have described a series of dielectrics designed for use over a wide variety of temperatures. This paper will focus on the characterization of a formulation (HT- 300) developed specifically for use near 300oC. Capacitance and resistivity measurements, Weibull breakdown statistics, and lifetime testing will be described for MLCCs ranging from 100-1000nF with voltage ratings of up to 500V.