OBJECTIVE: To identify the prevalence of injuries occurred during training and/or competition in triathlon athletes at SESC Triathlon Caiobá-2011. METHODS: One hundred and ninety athletes participated in the study (153 males and 37 females). RESULTS: Athletes reported time of practice between 3 to 6 years (20%), training frequency of 5 days per week (48%), at least one injury during trainings (76%). The prevalence of injuries according to the sports category was: running (79%), cycling (16%) and swimming (5%). The most injured region during training (39%) and competition (46%) was the calf. Female athletes reported 92% of injuries during running training and 35% of those injuries were on ankle and foot. During competition only two athletes reported injuries. Muscle injury was the most prevalent (54%) among male athletes, followed by tendon (19%), ligament (17%) and bone (9%) injuries. Among female athletes prevalent injuries were: 32% muscle, 32% bone, 32% tendon and only 4% ligament injuries. CONCLUSION: Skeletal muscle injuries were the most commom lesions during running training, however, male athletes reported mostly calf injuries, while female had mostly ankle and foot injuries. Level of Evidence III. Study of Non-Consecutive Patients; Without Consistently Applied Reference ''Gold'' Standard.