Brazilian jiu-jitsu (BJJ) is a grappling-based martial art which can lead to injuries both in training and in competitions. There is a paucity of data regarding injuries sustained while training in Brazilian jiu-jitsu both in competitive and non-competitive jiu-jitsu athletes. Our primary objective was to determine the prevalence of injuries sustained during jiu-jitsu training and competition. Our secondary objectives were to describe the types of injuries, and to determine which participant and injury characteristics are associated with desire to discontinue jiu-jitsu following injury, and characteristics are associated with requiring surgery for an injury. We conducted a survey of all BJJ participants at one club in Hamilton Ontario. We developed a questionnaire using focus groups, key informants and the previous literature. The questionnaire included questions on demographics, injuries in competition and/or training, treatment received, and whether the participant considered discontinuing BJJ following injury. The primary analysis was descriptive. The secondary analysis consisted of unadjusted logistic regression analyses to evaluate the association between selected demographic and injury patterns and those who considered quitting jiu-jitsu as a result of their injuries as a dependent variable. Seventy BJJ athletes participated in this study (response rate 85%). The majority of respondents were male (90%), over the age of 30 years (58.6%), and junior trainees (white belts [37.2%] or blue belts [42.9%]). Ninety one percent of participants were injured in training and 60% of competitive athletes were injured in competitions. Significantly more injuries were sustained overall (p < 0 .001) for each body region (pā¼0.001) in training in comparison to competition. Two-thirds of injured participants required medical attention, with 15% requiring surgery. Participants requiring surgical treatment were six and a half times more likely to consider quitting compared to those requiring other treatments, including no treatment (OR: 6.50, 95% CI: 1.53ā27.60). Participants required to take more than four months off training were five and a half times more likely to consider quitting compared to those who took less time off (OR: 5.48, 95% CI: 2.25ā13.38). We identified that nine out of ten jiu-jitsu practitioners surveyed suffered injury while in training and the most severe injuries for the majority of practitioners occurring during training. The most common injuries identified involved the fingers, neck, knee, and shoulder, with the majority of respondents seeking medical or surgical treatment or requiring physiotherapy or rehabilitation. Potential participants in BJJ should be informed regarding significant risk of injury and instructed regarding appropriate precautions and safety protocols. BJJ practitioners and instructors should be especially cognizant of safety during training, where the majority of injuries occur.