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In order to make clear the relationship between ƒ¢KIIth and ƒ¢ KIIIth and theinfluence of the rolling texture, Mode II and Mode III fatigue crack growth tests werecarried out for annealed 0.47 % carbon steels (JIS S45C).The values of ƒ¢KIIth (9.5MPa m and 9.7 MPa m ) for crack growth normal to the rolling direction were higherthan the values of ƒ¢KIIth (8.8 MPa m and 8.1 MPa m ) for crack growth parallel to therolling direction. Mode II and Mode III fatigue crack growth produced darkly etchedmicrostructural layers in the vicinity of Mode II and Mode III fatigue crack. Vickershardness of the layers was much higher than that of the original matrix (Mode II: HV 164¨ HV 468. Mode III: HV 175 ¨ HV 678). The layers consisted of very fine grains withthe size ranging from 100 to 200 nm. The value of ƒ¢KIIth was approximately equal to ƒ¢KIIIth,i.e. ƒ¢KIIth . ƒ¢KIII th . 9.6 MPa m for crack growth perpendicular to rolling direction.Therefore, the mechanism of Mode II fatigue crack growth is presumed to be essentiallyidentical to that of Mode III fatigue crack growth.