Background: Triathlon is a unique, rapidly growing sport that encompasses three disciplines: swimming, cycling and running. Triathlon distances can vary greatly and injuries occur as a result of an individual leg of the event, or as a result of a combination of the three. The likelihood of overuse-related injuries is vast. Methods: The current scientific literature was investigated using online web databases: Medline, Cinahl and Mantis. Triathlon, Triathletes and Injuries were the terms used for this search. Additionally the reference lists of selected papers (not found in the original search) were examined for relevance to the topic. Results: A review of past epidemiological triathlon studies is presented. The incidence of injury varied between 37% and 91%. Each discipline of triathlon has characteristic areas of the body that are susceptible to injury, mostly of an overuse, mechanical nature. The lower limb, particularly from the running component, produced most injuries. Most studies identified triathletes seeking some form of medical care. Discussion: Methodological analysis and limitations of past epidemiological triathlon studies are discussed. In addition, the basic mechanics of the swim, cycle and run phases are discussed to illustrate the contribution of these factors on common overuse musculoskeletal injuries, including exhaustion-related conditions. Each of the three disciplines has unique, sport-specific injuries. Conclusion: Triathlon is a growing sport with wide participation. This review alerts the practitioner to the potential causes of injury and encourages the practitioner to liaise with relevant coaches to seek a greater knowledge and understanding of triathlon injuries.