The use of compressed natural gas as a clean fuel in the transportation sector is growing around the world. Moreover, regarding the growth of vehicle use in Iran and due to the higher fixed investment requirements, finding the suitable locations is an important issue. The flow refueling location model is one of the models that have proposed recently to find refueling locations. In this study, finding the best CNG locations for two major suburban routes of Tehran consist of Tehran- Firoozkooh and Tehran- Semnan has been studied using the flow refueling location model. The results showed that the selected place to build a CNG station in Tehran- Firoozkooh route is at the end of Tehran-Damavand road before the Boomehen fire station with geographical coordinates (35.74,51.85) and the selected place to build a CNG station inTehran-Semnan route is in the Eyvankeh petrol station in the beltway Eyvankeh with geographic coordinates (35.35,52.05).