In the last years, the study of L-Citrulline as a supplement has been gaining interest due to its possible applications over the performance in sports. L-Citrulline is a non-essential aminoacid which can be obtained from vegetable or animal sources. This supplement is a precursor of Nitric Oxide, Arginine and has a principal role in the urea cycle. These factors presuppose that the consume of this ergogenic aid could have positive effects over the sport performance. The purpose of this study was to make a systematic review with which verify the efficacy of L-Citrulline or Citrulline Malate over various determinants parameters over the sport performance and other variables such as perception of effort and physiological factors in endurance sports. To achieve this objective, a research of the existent studies referred to the analysis of the sport performance after the consumption L-Citrulline was made. Finally, 7 studies were obtained and used to make this systematic review. After the analysis of the collected data it can be said that L-Citrulline or Citrulline Malate might have a positive impact over the sport performance. Nevertheless, a consensus must be made in order to achieve the standardization of the protocols and test used in the different studies to say that this supplement has a significant positive impact over the athletes performance.