This paper is concerned with crash analysis for a front side member of an auto-body considering the effect of fabrication. The front side member is fabricated with sheet metal forming processes that induce forming histories such as the plastic work hardening and non-uniform thickness distribution. Numerical simulation is carried out with LS-DYNA3D in order to identify forming effects on the crashworthiness. The crash analysis of the front side member with the forming effect leads to a different result from that without the forming effect. Crashworthiness factors such as the load-carrying capacity, the crash mode and the energy absorption are calculated to investigate and identify forming effects. It is fully demonstrated that the design of auto-body members needs to consider the forming effects for accurate assessment of the load-carrying capacity and the deformation mechanism of the formed members.