Abstract-Fatigue crack propagation tests were carried out under pulsating stress, partly alternating stress and zlternating plastic fatigue for Cr-Mo-V steel and mild steel. Although stress and strain intensity factors do not effectively correlate the fatigue crack growth rate over a wide range of stress and strain conditions, a normalized fatigue crack growth rate [(da/dN)/a] is related to the strain range. The fatigue crack propagation behavior at a notch under pulsating load is analyzed with the above relation by considering the cyclic elasticplastic condition at the notch.