The importance of genetic factors in the pathogenesis of diseases is well established. Association between different pathologies and their gene expression may improve treatment and knowledge about them. There are some important studies about gene expression analysis and anterior cruciate ligament (ACL) injury. A familial relationship of ACL injuries has been described. Also, studies have shown a relationship between ACL injury and genes of different types of collagen, such as collagen type 1 (COL1A1),type 3 (COL3A1), type 5 (COL5A1), type 12 (COL12A1), type 14 (COL14A1) and type 15 (COL15A1). Nonetheless, gene factors that are responsible for metalloproteinase, proteoglycans and angiogenesis-associated signalling pathway have been correlated to the risk of ACL rupture. Despite the fact that the relationship between gene expression and genetic polymorphism and ACL injury is not nearly fully understood, current data present new interesting facts. Further studies may help us understand the actual importance of genetic factors and aetiology of ACL tears, which could ultimately lead us to new approaches in the prevention and treatment of these injuries.