Foam materials such as polyurethane play a very important role as the shock and energy absorbing material in many kinds of impacts. Recent interest in the numerical analysis of side impact testing coupled with the strong influence that such a material has on the impact response have made the determination of an appropriate material model for foam mandatory. The typical mechanical behavior of this material, which should be considered in the numerical material model, can be described as highly non-linear and strain-rate dependent with high energy dissipation characteristics. Such a material also possesses hysteresis characteristics in cyclic loading. Specific numerical parameters are required in order to adequately model the behavior of this material. The main objective of this paper is to present a method of determining these parameters and provide some examples of the effect of these parameters in the chest impact simulation of the DOT-SID dummy.