Nowadays BPR has become as one of the most widespread and safe management topics and a redeemer for organizations which are in the stage of destruction and ruining. Although many organizations use BPR to improve their performance, researches show that about 70-80 percent of these projects were failed and remain unfinished. Many researches have been even undertaken to find out reasons of these failures. Lack of an adequate methodological approach and perception and using non-adequate tools and techniques in its implementation, are some of the main reasons for these failures. Using computer simulation in modeling and analyzing the process is one of the best and most adequate BPR techniques which can decrease these failures and increase their implementation success. In this paper, following an application and also case study research methodology, 51 BPR and 24 Simulation methodologies, approaches and techniques were considered and on the basis of Kettinger et al.'s research method done in the BPR area to develop a compound methodology for BPR, a comprehensive combined methodology using simulation technique was presented. Finally the results of a project done using this methodology in a process of NIORDC (National Iranian Oil Refining and Distribution Company) were presented.