Liquid helium and liquid nitrogen are commonly used as coolants for highly frequency stable oscillators. In this paper. e present the use of solid nitrogen as an alternative coolant. Solid nitrogen solidifies near 52 K under vacuum and we show that the temperature fluctuations in the solid are an order of magnitude lower than in the liquid. This has the advantage of reducing the temperature control requirements necessary to limit temperature induced frequency fluctuations in cryogenic microwave resonator-oscillators, (C) 2002 Published by Elsevier Science Ltd.