Purpose: This study aimed at investigating the effect of carbohydrate (CHO), caffeine (CAF) and a guarana complex (GUAc) ingestion during a running exercise on cognitive performance, ratings of perceived exertion (RPE) and shooting performance in high level Modern Pentathlon athletes. Methods: Ten athletes completed four counterbalanced sessions within a 2 week-period, corresponding to ingestions of CHO (30 g), GUAc (300 mg), CAF (200 mg) or placebo (PL). The exercise involved a 40-minuterunon a treadmill atasteady speed, previously determined as a “somewhat hard” exercise (RPE 13). Shooting and cognitive performances (Simon task) were assessed in three phases: 1) prior to exercise and ingestion, 2) prior to exercise and after half ingestion, and 3) after exercise and full ingestion. Ingestions were consumed 40 minutes (250 ml) and 5 minutes (125 ml) prior to exercise, and after 20 minutes of run (125 ml) . RPE was assessed at 10minutes intervals during exercise. Results: Results have shown an interaction between drinks and exercise on mean reaction time (p = .01, ɳp2= .41) and a drinks effect on RPE (p = .01, ɳp2= .15). CHO, CAF and GUAc enhanced the speed of information processing after exercise (respectively p = .003, p = .004 and p = .04) but only CAF and GUAc decreased RPE (respectively p = .002, p = .02). Conclusion: Our results highlight the beneficial effect of nutritional supplements on information processing and RPE. This finding is particularly interesting since decision-making processes are vitalin many sports performance.