The fatigue strength of structural elements may be limited by the presence of short cracks, which can not be detected with traditional nondestructive inspections. The behavior of these cracks can be modeled using the characteristic size of short cracks a0, proposed by El Haddad, Topper and Smith (ETS), which allows one to properly adjust experimental data from the Kitagawa-Takahashi diagram. Based on the ETS model, this work presents the Stress Gradient (SG) model, developed to predict the effect of short cracks that grow from the notch tips. This model considers that cracks are easily generated due to fatigue in sharp notches, which introduce high stress concentration effects at their tips. Because of the high stress gradient acting at these notch tips, the short cracks can also stop to grow by fatigue after having propagated through a small distance, thereby becoming non-propagating cracks that can be tolerated in service. C(T) modified specimens were specifically designed to study the generation and initial growth of these cracks in fatigue tests, and used to experimentally verify the predictions of the proposed model.