RFID (Radio Frequency Identification) is an Auto-ID technology which uses radio waves to automatically identify the individual items. Using RFID systems for identifying and tracking objects, it is possible to improve the performance of a supply chain process in terms of operational efficiency, accuracy and security. RFID systems can be implemented in different levels like item, case or pallet. These various applications create different impacts in supply chain processes. RFID investments are very important strategic decisions so they require a comprehensive evaluation process. The tangible and intangible benefits should be integrated to evaluate them. The fuzzy cognitive mapping (FCM) is a suitable tool to model causal relations in a non-hierarchical manner for an RFID investment evaluation. In this paper, the FCM method is used to measure the impact of RFID investment in a supply chain process.