The Cockcroft-Latham (CL) damage factor has been calculated, using FEM simulation, during equal channel angular extrusion (ECAE) of strain hardening materials. A high CL damage factor was predicted inside the billet and the damage was increased with the increasing strain hardening coefficient. This was closely related to a generation of increasingly high tensile stress in the deformation zone inside the billet due to an inhomogeneous deformation. The possibility of cracking inside the ECAE billets was confirmed in the ECAE processing of Ti-0.34O-0.95Fe and Ti-0.5Fe billets. The simulation further predicted that CL damage factor can be reduced by applying back pressure or friction force.