The aim of this work is to take into account the effect of the stress gradient as a beneficial effect in fatigue, since its presence within a material systematically leads to an increase in the endurance limit in terms of local maximum stress. We have therefore proposed that the stress gradient be taken into account in the fatigue criterion using a statistical approach based on the variance method. This method assumes that the fracture plane is the one on which the variance of the equivalent stress is maximum. This method defines three types of equivalent stress on a plane: normal stress, shear stress and combined normal and shear stress. The results obtained using the simple variance method and the stress gradient method were compared for a cyclic biaxial loading condition. We found that in terms of prediction of the fracture plane, there is not much difference between the two formulations (the simple variance method and the one taking into account the stress gradient), but the maximum values of the variance for the variance method taking into account the stress gradient vary greatly compared to the case of the simple variance method.