Abstract: Poor cardiovascular fitness has been implicated as a possible mechanism for obesity- related cognitive decline, though no study has examined whether BMI is associated with poorer cognitive function in persons with excellent fitness levels. The aim of this study is to investigate the relationship between body mass index and cognitive performance in rugby players. Thus, fifteen rugby players male aged 24.7 ± 0.9 voluntarily participated in this study, whose body mass index (BMI) was greater than 30.