This study evaluates whether 7-day creatine monohydrate supplementation affects cognitive function after high-intensity interval training (HIIT) in active young men. Twenty participants were assigned to one of four groups: placebo plus exercise, placebo without exercise, creatine 0.1 g/KgBW/day plus exercise, or creatine 0.3 g/KgBW/day plus exercise. Cognitive performance was measured before and after the intervention using visual reaction time, go/no-go visual reaction time, and Trail Making Tests A and B.