By talking about complex systems, systems engineering is always named as the only way out for the enhancement of system understanding and the reduction of system complexity in the design process. After an identification of the essential aspects and concepts for pursuing systems engineering, this paper shows how well these key factors are integrated in today’s methodologies for developing mechatronic and cybertronic systems. The content of this paper is based especially on current and previous research activities on the field of model-based development at the Institute of Virtual Product Engineering.