Gaona KL. Comparative study of musculoskeletal injuries in transport aircrew. Aviat Space Environ Med 2010; 81:688–90. Introduction: Musculoskeletal (MS) injuries causally associated with aircraft or aircrew positions pose a threat to safety and readiness. The purpose of this study was to compare and contrast MS injury rates between C-5 and C-17 aircrew members at Travis Air Force Base. Methods: Data were collected retrospectively from the Duties Not to Include Flying (DNIF) log maintained at the Flight Medicine Clinic. Active duty C-5 and C-17 aircrew MS injuries documented in the log from May 2008 to May 2009 were analyzed. Results: A total of 63 injuries were identified in a 12-mo period that resulted in DNIF status. Of the total, 12 (19.1%) were pilots, 13 (20.6%) were flight engineers, 37 (58.7%) were loadmasters; 58 (92.1%) were men and 5 (7.9%) were women. C-5 aircrew represented 57.1% of the reported injuries; C-17 aircrew represented 42.9% of the reported injuries. The findings did not indicate a difference between C-5 and C-17 aircrew MS injuries; however, loadmasters were at an increased risk. Increased age and body mass index also correlated to an increased risk of MS injuries in the C-5 and C-17 community. Discussion: C-5 and C-17 loadmasters are at an increased risk of MS injury based on aircrew position. However, 67.6% of loadmaster's injuries were reported as not duty-related, suggesting that off-duty actions are potentially affecting mission readiness and safety. These findings supported the importance of maintaining good physical condition as a preventative safety measure against MS injuries.