To determine the difference, if any, in the physiological characteristics of mixed martial arts athletes and traditional martial arts athletes. Twelve male participants age 18 to 36 yr volunteered for the study. Group 1 (n = 6) was comprised of professional and amateur mixed martial artists from northern Louisiana. Group 2 (n = 6) was traditional martial artists recruited from a local karate tournament. Each group performed the same tests. Tests included height, weight, body composition (TanitaTM bioelectrical impedance device), flexibility (sit and reach), leg power (vertical jump), muscular endurance (1-minute push-up and 1-minute sit-up), grip strength (20.5 kg plate hold), muscular strength (1 rep max bench press), and o2max. Body composition was the only significant difference (p < 0.05) between the 2 groups. The mixed martial artists were significantly leaner than the traditional martial artists. This was not surprising because class separation for traditional martial artists goes by age rank, while mixed martial arts competition is broken down into weight classes. In order to compete in a lower weight class, mixed martial artists reduce their body mass to make a specific weight class. In doing this, percent body fat is typically reduced. There were 2 major limitations to this study. One was the timing of testing. The traditional martial artists were tested 1-2 hr after competing in a karate tournament, while the mixed martial artists were tested weeks before their next fight. The other limitation was the number of participants. Though only one significant difference was found between the groups, it can be suggested that a high level of physical fitness is essential for performance in mixed martial arts and traditional martial art competitions. Mixed martial artists usually train at high intensities with various forms of interval training to improve their aerobic capacity. This helps condition them for their fights. Although o2max was not found to be significantly different between the 2 groups, there was a trend for the mixed martial artists having higher aerobic capacities. Had there been more participants and lower standard deviations for o2max, this variable may have been significantly different. Future studies should attempt to test the groups during the same time frame, have more participants, measure psychological characteristics, and consider using a DXA scan to measure bone mineral density. Acknowledgments: We would like to thank Dr. David Jordan for letting us use his tournament to recruit participants.