From a qualitative point of view it is well known that thermo-chemical treatments may change substantially static and fatigue resistance properties of steel, usually improving them. Nevertheless quantitative measures of the effects of these treatments frequently are not available. Aim of this work is the evaluation of the effect of carburizing and tempering on a steel utilized in the automotive field. Static and fatigue characterization has been performed on the material in the annealed and carburized-tempered (C-T) state. Different methods for the evaluation of the fatigue limit have been employed leading to significantly dissimilar results.