Triathlon is a very complex sport, as the athlete has to master the characteristics of three sports (swimming, cycling and running), and the tasks of coaches are increased by the need to get the most out of all three. This sport improves endurance, has a positive effect on muscle development, movement coordination, breathing, and circulation. For talent identification factors determining the performance in triathlon are essential (physiological, anthropometric, psychosocial and tactical factors). Scientific literature concerning performance in triathlon sport is rather scarce. Although there are some studies in this field, there is little comprehensive literature analyzing training of youth athletes. The aim of our research was (i) to conduct a targeted literature review of the body composition and performance of youth triathletes and (ii) comparing results with those of elite adults, (iii) determining factors playing a prominent role in the selection and performance of triathletes. The results of our research reveal that factors like the appropriate competition age (approx. 28-30 years for both sexes), anthropometric parameters (it is necessary to take into account the distance the athlete covers) and performance criteria (themost important isVO2max) are essential for successful selection and subsequent success. In the world of triathlon constant regulatory changes and the need to adapt new competitive demands necessitate keeping our knowledge up to date.  Kulcsszavak: triathlon, youth athletes, selection, talent, evaluation