Nowadays, the main attention and tendencies of tourists are towards ecotourism and its related activities. Ecotourism centers are an active business in the ecotourism industry that provides necessary services for tourists. Today, the number of ecotourism centers in some areas is increasing and it caused an intensively competitive environment between these centers to attract customers. In other words, the big concern of the manager and owners of these centers is knowing the variables which affect the decisions of tourists to choose an ecotourism center. From what we know, no research has been done on this subject. Therefore, these matters encouraged us to do an essential investigation. In this paper, firstly, the factors affecting a tourist's decision to choose an ecotourism center are identified. Three types of customers (tourists) are considered for ecotourism centers and the weight of each of the considered factors is calculated using the fuzzy DEMATEL method based on the opinion of each customer group. Then, the factors are ranked using the TOPSIS method. The outcomes manifest that the personnel of the centers and the brand of each center have the most and the least impact on the selection process by the tourist, respectively. Manuscript profile