Abstract: The purpose of this study was to identify which was the determinative factor of the competencies needed to manage health and fitness clubs and indoor sport facilities in Greece. For the collection of the data we used an instrument validated by a sample of 101 health and fitness clubs and indoor sport facilities managers. The final sample of the study was 401 sport directors in the municipalities, selected randomly. Exploratory factor analysis with varimax rotation revealed that sport science was the determinative factor, comprising 12 competency statements. The internal validity revealed a Cronbach’s alpha factor of 0.87 with a factor-loading ranging from 0.889 to 0.616. The items rated by managers demonstrated an understanding of: (a) human limitations in sport (factor loading 0.889), (b) the prevention and rehabilitation of injuries (factor loading 0.873) and (c) exercise physiology and anatomy (factor loading 0.872). These results show that the determinative factor of competencies needed to manage health and fitness clubs and indoor sport facilities are closely related to sport science.