Abstract <p>Low cycle fatigue (LCF) behaviour of carbide-free nanostructured bainitic steels was studied under fully reversed axial strain control at a constant strain rate of 5 × 10⁻³&#xa0;s⁻¹ to investigate the effect of stability of retained austenite in them, on their LCF resistance. LCF was investigated using symmetrical triangular waveform over the total strain amplitude from ± 0.50 to ± 0.80 pct, at room temperature. Cyclic hardening was observed upto about 100 cycles at the lower strain amplitudes of ± 0.50 and ± 0.60 pct, however, the cyclic stress response at the higher strain amplitudes of ± 0.70 and ± 0.80 pct was different for the three steels. Strain-induced martensite was observed by X-ray diffraction (XRD), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) examination in the fatigue tested samples of all the three steels. Secondary electron microscopy (SEM) examination of the fractured samples revealed single site of crack initiation from surface and striations during crack propagation. The B15VA-2 alloy steel, which is chemically stable but mechanically less stable than B12VA-2 and B14VA-2 steels was found to exhibit highest fatigue life.</p> Graphical Abstract <p></p>