The aim of this study was to identify the constituent elements of the Iran sport federations system and to examine their relationships. Systematic approach was considered for systematic examination of the constituent elements. By reviewing the theoretical literature and interviews with knowledgeable elites, the constituent elements of sport federations system including inputs (financial resources, sport facilities, human forces and leadership and management), processes (preparation and development of coaches, promotion and media, national and international competitions and camps, scientific and research development, sport participation, talent identification, elite athletes development and support), outputs (growth and generalization of sport, success and medaling), and outcome (development) were identified. The assessment of the relationship between each of these variables can be considered as a decision-making. Therefore, DEMATEL test could be used to extract causal relationships of variables. In this paper, 12 sport management experts examined the relationship of these variables. The results showed that national and international competitions was the most influential element and developing elite athletes was the most affected element. In addition, element of developing elite athletes had maximum intensity (total of affecting and affected). The element of scientific and research development was a strong penetrator and talent identification was a strong penetrated element. Finally, this study can help sport managers to systematically understand sport federations and their causal relationships.