Whereas clinical professionals and the general public recognize exercise in moderate amounts as an important component of a healthy lifestyle, researchers have noted that when taken to an excessive level, exercise may become addictive. Usually considered rare in the broad exercising population, risk for exercise addiction has been found to be more prominent among certain specialized groups, such as runners. This study investigated the risk for exercise addiction in a unique group of endurance athletes-Sprint-, Olympic-, Half-Ironman, and Ironman-distance triathletes. The sample consisted of 1285 male and female triathletes, ranging in age from 18 to 70 years old, recruited through the electronic newsletter of a national triathlon organization. During the past year participants completed at least one triathlon of Sprint-, Olympic-, Half-Ironman-, and/or Ironman-distance, or were in training for one. To measure the risk for exercise addiction, participants completed an online questionnaire, comprising the six items of the Exercise Addiction Inventory (Terry, Szabo, & Griffiths, 2004), six items added by the investigator, and a demographics section. Results indicate that approximately 20% of triathletes are at risk for exercise addiction, 79% are committed exercisers who exhibit some symptoms of exercise addiction, and 1% are asymptomatic. Results also demonstrate that female triathletes are at greater risk for exercise addiction than male triathletes. Training for longer distance races (e.g., Olympic-, Half-Ironman-, and Ironman-) put triathletes at greater risk for exercise addiction than training for shorter races. No significant association exists between the risk for exercise addiction and either the number of years of participating in the sport or the length of training sessions. However, as the number of weekly training hours or the number of weekly training sessions increases, so does a triathlete's risk for exercise addiction. Results demonstrate that triathletes have a lower than anticipated risk for exercise addiction, yet a higher risk than the general exercising population. Because at-risk triathletes need greater clinical attention, further research should be conducted to help clinicians develop enhanced awareness and appropriate interventions.