Automotive engineering requires dynamic system simulation software. To meet future legislated emission and con-sumption standards, a vehicle has to be considered as a group of interacting systems. NAGREMA is an automotive simulation software with the focal point on the accessory drive. Variations of the standard V-belt configuration can be compared with decentralized approaches using electric or electro-hydraulic drives. NAGREMA is implemented using MATLAB/Simulink, provides a graphical user interface and a set of vehicle, engine and accessory templates. It reduces model complexity by dividing the vehicle, the engine, the accessory drive and the control system into hierarchically organized subsystems.