We aim to investigate the effect of narcissism as a personality factor on endurance performance task. We measured participants’ narcissism with self report measures of the Narcissistic Personality Inventory-16 and their perception of effort via the Ratings of Perceived Exertion. We then obtained participants’ psychophysiolo- gical measures such as heart rate, heart rate variability and also body mass indexes. The final sample comprised 66 individuals (Mage=18.48; SD=1.50, n= 27 women, n= 39 men). All participants twice performed a multistage 20-meter shuttle run test in the same-sex teams of three: once when identifiability was low (team condition); and once when identifiability was high (individual condition). Our results revealed that narcissists’ performance significantly decreased from individual to team condi- tions, whereas others displayed no such performance differences. Our results support the hypotheses that narcissists performed better when there was a chance for glory and socially loafed when no such opportunity was available. Results of the present study provide a sound basis foundation for future studies (i.e., endurance sports) on which to explore narcissism as individual differences in the competitive environment.