A study on the effect of changing the principal stress axes on low-cycle fatigue lives was carried out in four strain waveforms at 923 K in air using SUS 304 austenitic stainless steel. No effect of alternation of axes on fatigue lives was observed at that temperature. But comparison of this result with a former result at 823 K, in which the alternation of axes is detrimental to fatigue lives, shows that the effect of the alternation of axes is connected closely to the fracture mode, that is, transgranular at 823 K and intergranular at 923 K. When the specimen fractured transgranularly the alternation of axes decreases the fatigue life, but, when the specimen fractured intergranularly, no effect is noted. This phenomenon is not affected by the strain waveform. Detailed discussion on the fatigue life is made from crack initiation and propagation considerations.