EN
The paper studies the methodological foundations of modeling business processes as part of their economic activity in reengineering. Noted features of modern economic systems that determine certain characteristics of business process management, including their reengineering. Proved problematic in the implementation of business process modeling with their further reengineering. The directions of the theory of self-organization of complex systems. Defined methodological principles of construction of systems modeling business processes during their reengineering. The stages of the business process modeling, which redesigns. Studied reengineering financial performance of industrial enterprises in the current economic conditions using simulation. The application of models of Baumol and Miller-Orr during business process modeling in their reengineering. Formed corresponding conclusions on research within the scope of this article.