Even though the use of thermography as a non-destructive testing method is relatively well known, its use as a reliable tool for measuring the fatigue properties of metals is not. However, analyzing the temperature rise on the external surface of a structural component during cyclic loading can provide a reliable measure of its fatigue limit, avoiding the need for destructive tests and requiring much less time than standard test methods. It s also possible to determine the SN curve and the influence of the mean stress on its behavior through the same methodology, correlating an energy parameter with the assumption of its dependency on the stress amplitude. For the accomplishment of this work two metallic alloys were chosen, the C36000 brass alloy and 6351-T6 aluminium alloy. The results presented here show good agreement between the predicted and measured fatigue limits and mean stress influenced SN curves.