Fatigue tests were carried out at different stress levels on cruciform welded joints made from mastensitic stainless steel. The purpose of the present paper was to verify the validity of the thermographic method and to extend its capability on welded structural evaluation, considering the real operating situations. Due to limitations of the traditional fatigue test, the infrared thermographic technique was developed to predict and assess the fatigue limit and the entire S-N (Stress-Life) curve of cruciform welded joints. Through the comparison, the predictions of the fatigue behavior by the thermographic method (TM) manifested good agreement with the traditional method. The present research paper concludes that the TM as a promising method enables us to rapidly obtain reliable fatigue characteristics of welded structural components.