An automobile door is one vital commodity which has its role in vehicle’s function, strength, safety, dynamics and aesthetic parameters. The door system comprises of individual components and sub-assemblies such as door upper, bolster, armrest, door main panel, map-pocket, handle, speaker and tweeter grille. Among them, armrest is an integral part which provides function and also takes care of some safety parameter for the customers. The basic function of an armrest is to provide ergonomic relief to occupant for resting his hand. Along with this, it also facilitates occupant safety during a side impact collision by absorbing the energy and not imparting the reactive force on occupant. Thus an armrest has evolved as a feature of passive safety. The armrest design should be stiff enough to withstand required elbow load condition with-in the acceptable deflection criteria. On the other hand, armrest has to absorb the dynamic force by deflecting proportionally to the side impact load. In this study the various structure of armrest was analyzed to strike an ideal zone between functional and safety parameters. The scope is to improve the functional requirement, i.e., the side impact metrics and also to reduce the variation among the noise factors such as manufacturing tolerance, location of side impact and BIW rigidity. For this, DFSS way of approach is handled to optimize a robust design which provides enhanced passive safety for customer. This optimized passive safety armrest design can be used for upcoming programs and the development lead time can be reduced considerably.