Some simulation tools have been developed to support business process reengineering. These tools can be used to not only analyze an as-is model of the existing process but also assess the potential value and feasibility of to-be models. But most of them are restricted to analyzing and redesign of the workflow only. Little attention is paid to the organization of people and their roles. This paper Presents a new methodology for business process simulation modeling and analysis. The methodology is based on the concepts of roles and customer-supplier chains. So the proposed methodology allows for tracking people and their roles affected by reengineering the business process. It enables one to analyze and evaluate not only workflow, but roles that are part of the flow. This paper developed a simulator to systematically construct simulation models and conduct simulations easily and efficiently. A case study is also presented as an illustrative example.