Department of Defense policy prohibits, with limited exceptions, transgender individuals from serving in their affirmed gender in the U.S. Military, citing potential impact on unit cohesion and military readiness. To date, however, little is known about the sociodemographic profile and health of transgender military personnel. Methods: U.S. Military personnel who self-identified as transgender completed anonymous online measures of demographics and military service. Participants also completed measures of health, mood, eating pathology, and risk behaviors. Results: One hundred ninety-five service members (mean age: 28.9-7.2 years, 48.7% transmale, 70.3% non-Hispanic White, 7.83-5.9 years in service) completed the survey. The majority of respondents first identified as transgender before military accession. Most had disclosed their gender identity to their command and providers, and had undertaken steps toward gender affirmation. The sample as a whole reported above average physical health, with mood symptoms within normal ranges and few reported risk behaviors. Analyses of covariance indicated that transmales reported significantly better mental health and psychosocial functioning compared with transfemales. Conclusion: In light of current policy that precludes, with limited exceptions, transgender individuals from serving in the U.S. Military in their affirmed gender, the current study provides an initial sociodemographic profile of this understudied population and indicates that transgender service members report above average physical health and few risk behaviors. Preliminary analyses indicated that transfemales in the military may be at higher risk for mental health concerns, compared with transmales. Additional research is needed to elucidate risk and protective factors among transgender service members.