The uniaxial, reverse cyclic fatigue performance of a commercially available hot isostatically pressed silicon nitride was examined at 1370 degrees C in air and with a 1 Hz sinusoidal waveform using button-head tensile specimens. Specimens did not fail in less than 10(6) cycles when the applied stress amplitude was less than 280 MPa. Slow crack growth occurred at stress amplitudes greater than or equal to 280 MPa and failure always occurred during the tensile stroke of the waveform. Multi-grain junction cavities resulted (i.e., the accumulation of net tensile creep strain) as a consequence of the reverse cyclic loading even though the specimens endured half their life under tensile stresses and the other half under compressive stresses. The presence of multi-grain junction cavities was a consequence of the stress exponent of tensile creep strain being greater than the stress exponent of compressive creep strain. Lastly, it was observed that the static creep resistance of this material improved when it was first subjected to reverse cyclic loading at 1370 degrees C for at least 10(6) cycles at 1 Hz. Silicon nitride grain coarsening (which was a consequence of the completion of the alpha to beta silicon nitride solution/reprecipitation process that occurred during the history of the reverse cyclic loading) lessened the capacity for grain boundary sliding resulting in an improved static creep resistance.