: Today, discrete-event simulation (DES) use in the manufacturing industry has become widespread, but far from all companies use this technology.Often simulation is used on a `one-shot' basis only, or as a standalone tool, reflecting a low level of integration. At the same time, a majority of companies do not use simulation at all. It is argued here that these companies lack methodologies for adopting and integrating simulation into their manufacturing system development process. Also, simulation research on integration aspects often deals with specific functional, or data-level issues, such as integrating and connecting simulation to other systems and tools, rather than structural, hierarchical, and procedural integration aspects as part of a methodological approach. Furthermore, simulation use seems to lack strategic focus. Based on industrial experience, this paper presents the framework of a methodology for integrating discrete-event simulation into manufacturing system develo...