This paper presents a system developed for online monitoring of various aging effects, such as fatigue, creep and fatigue–creep interaction. An appropriate life prediction methodology has been used to address the various aspects of creep, fatigue and creep fatigue interaction, creep and fatigue crack growth. The system converts the plant transients to temperature and stress responses using the analytical models modified by FEM. The fatigue usage factor is computed using the rainﬂow cycle counting algorithm. The creep damage index is evaluated from the computed temperature and stress histories and the material creep rupture curve. This system has already been installed at Henan Jiaozuo power plant in china for monitoring the fatigue and creep degradation.