ObjectiveTo study risk factors for injury in karate and to establish safety recommendations.DesignCross-sectional survey of karate injuries.SettingShotokan karate clubs in Boston, Massachusetts, Dallas, Texas, and Winnipeg, Manitoba, Canada.ParticipantsAll athletes training at each club received surveys. A total of 114 surveys were analyzed (74% response rate).Main outcome measuresPresence of injuries (requiring any time off from practice), major injuries (requiring at least 7 days off), and multiple injuries (3 or more injuries).ResultsNo statistically significant differences were found with respect to sex. For all outcomes, karateka younger than 18 years of age had fewer injuries. The number of karateka with injuries and with multiple injuries increased with belt rank until brown belt, then reached a plateau. Brown and black belts had a greater frequency of major injuries than the lower ranks. Training more than 3 hours per week correlated with an increase in injuries, major injuries, and multiple injuries.ConclusionShotokan karate appears to be a safe sport, especially for those younger than 18 years of age. Risk of injury increases significantly when younger karateka of any rank or older karateka of lower ranks train more than 3 hours per week; therefore, to reduce the risk of injury to less than 50%, weekly training should be limited to a maximum of 3 hours in these groups.