With the huge improvements made during the last years in the area of integrated safety systems, they are one of the main contributors to the massively rising complexity within automotive systems. However, this enormous complexity stimulates the demand for methodologies supporting the efficient development of such systems, both in terms of cost and development time.Within this work, we propose a co-simulation-based approach for the validation of integrated safety systems. Based on data measurements gained from a test bed, models for the sensors and the distributed safety system are established. They are integrated into a co-simulation environment containing models of the ambience, driving dynamics, and the crash-behavior of the vehicle. Hence, the complete heterogeneous system including all relevant effects and dependencies is modeled within the co-simulation. This allows validating the distributed integrated safety system by performing a number of fast and efficient co-simulation-based dynamic test runs with different external (e.g. environment) and internal parameters (e.g. configuration of the integrated safety system, different algorithms, and strategies). This helps the developer to get a comprehensive view about the complete integrated safety system, massively increasing the understanding of the complex overall mechatronic system.We demonstrate our co-simulation based approach for the validation of integrated safety systems by a camera-based system for the preventive protection of pedestrians.