Introduction: The knee joint is the largest joint in the human body. The main role of the anterior cruciate ligament is to prevent excessive anterior translation of the tibia. Due to the increasing involvement of people in sports, we encounter this injury more and more often, which can have a long recovery time. There are various methods of prevention, of which the most common method is still warming up and stretching. The aim of the research: The main aim of the research is to prove that the frequency of anterior cruciate ligament injuries in soccer players is higher at the professional and semi-professional level than at the amateur level. Specific goals arise from the main objective, which are to investigate the relationship between the occurrence of anterior cruciate ligament injuries and age, and to investigate the relationship between the number of anterior cruciate ligament injuries and the implementation of prevention procedures. Participants and sample size: According to a random sample, soccer players from various cities in Croatia and from various levels of competition will participate in the research. The minimum number of respondents is 100, of which a minimum of 15% is included in the statistical processing, that is, they had or currently have an anterior cruciate ligament injury. Their age is between 18 and 42 years. The research will be conducted through an online survey in May 2022. Results: Out of 101 respondents, 16 of them suffered an anterior cruciate ligament injury during their career. Out of those 16, only one respondent had this injury more than once. Also, out of 16 people with this injury, as many as 10 of them were at the amateur level of competition when they suffered the injury, and only one respondent out of all the injured was over 30 years old. The majority of respondents (86.5%) believe that their club pays enough attention to injury prevention, although the research did not prove a positive effect of prevention on the incidence of anterior cruciate injury. Conclusion: this research has proven that in professionals and semi-professionals, injuries to the anterior cruciate ligament do not occur more often than in amateurs. It was also concluded that a much more detailed study with more samples is needed in order to prove the importance of the athlete's age and the importance of prevention in the frequency of anterior cruciate ligament injuries.