Objective-To determine the type and number of injuries that occur during the training and practice of Muay Thai kick boxing and to compare the data obtained with those from previous studies of karate and taekwondo. Methods-One to one interviews using a standard questionnaire on injuries incurred during training and practice of Muay Thai kick boxing were conducted at various gyms and competitions in the United Kingdom and a Muay Thai gala in Holland. Results-A total of 152 people were questioned, 132 men and 20 women. There were 19 beginners, 82 amateurs, and 51 professionals. Injuries to the lower extremities were the most common in all groups. Head injuries were the second most common in professionals and amateurs. Trunk injuries were the next most common in beginners. The difference in injury distribution among the three groups was significant (p less than or equal to0.01). Soft tissue trauma was the most common type of injury in the three groups. Fractures were the second most common in professionals, and in amateurs and beginners it was sprains and strains (p less than or equal to0.05). Annual injury rates were: beginners, 13.5/1000 participants; amateurs, 2.43/1000 participants; professionals, 2.79/1000 participants. For beginners, 7% of injuries resulted in seven or more days off training; for amateurs and professionals, these values were 4% and 5.8% respectively. Conclusions-The results are similar to those found for karate and taekwondo with regard to injury distribution, type, and rate. The percentage of injuries resulting in time off training is less.