Work ROLLs in the HOT ring ROLLing process are susceptible to various damages due to the contact with HOT metal. Thermo-mechanical fatigue is one of these damages. In order to predict failure resulting from the thermo-mechanical stress in the work ROLLs, the developed code in ABAQUS was used. A comparison between three-and two-dimensional models was made and also, thermal and thermo-mechanical responses of work ROLLs with variable boundary conditions were investigated. The results demonstrated that by applying mechanical and thermal loads separately or simultaneously, the response of work ROLLs is completely different. In the mandrel, the location of the maximum equivalent stress is on the surface, while the location of equivalent maximum stress is on the subsurface of the main ROLL. Upon utilizing cumulative damage rules and the stress-life method, the thermo-mechanical fatigue life was estimated. The cumulated damage to the surface of the mandrel was higher than that to subsurface regions. In contrast to the mandrel, the cumulated damage to the subsurface of the main ROLL was higher than that to the surface regions. In HOT ring ROLLing machines, these locations are prone to crack initiation as a result of the thermo-mechanical fatigue of the work ROLLs.