Introduction Simulation-based medical training has been shown to be effective and is widely used in civilian hospitals; however, it is unclear how widely and how effectively simulation is utilized in the U.S. Military Health System (MHS). The current operational state of medical simulation in the MHS is unknown, and there remains a need for a system-wide assessment of whether and how the advances in simulation-based medical training are employed to meet the evolving needs of the present-day warfighter. Understanding the types of skills and methods used within simulation programs across the enterprise is important data for leaders as they plan for the future in terms of curriculum development and the investment of resources. The aim of the present study is to survey MHS simulation programs in order to determine the prevalence of skills taught, the types of learners served, and the most common methodologies employed in this worldwide health care system. Materials and Methods A cross-sectional survey of simulation activities was distributed to the medical directors of all 93 simulation programs in the MHS. The survey was developed by the authors based on lists of critical wartime skills published by the medical departments of the US Army, Navy, and Air Force. Respondents were asked to indicate the types of learners trained at their program, which of the 82 unique skills included in the survey are trained at their site, and for each skill the modalities of simulation used, i.e. mannequin, standardized patients, part task trainers, augmented/virtual reality tools, or cadaver/live tissue. Results Complete survey responses were obtained from 75 of the 93 (80%) MHS medical simulation training programs. Across all skills included in the survey, those most commonly taught belonged predominantly to the categories of medic skills and nursing skills. Across all sites, the most common category of learner was the medic/corpsman (95% of sites), followed by nurses (87%), physicians (83%), non-medical combat lifesavers (59%), and others (28%) that included on-base first responders, law enforcement, fire fighters, and civilians. The skills training offered by programs included most commonly the tasks associated with medics/corpsmen (97%) followed by nursing (81%), advanced provider (77%), and General Medical Officer (GMO) skills (47%). Conclusion The survey demonstrated that the most common skills taught were all related to point of injury combat casualty care and addressed the most common causes of death on the battlefield. The availability of training in medic skills, nursing skills, and advanced provider skills were similar in small, medium, and large programs. However, medium and small programs were less likely to deliver training for advanced providers and GMOs compared to larger programs. Overall, this study found that simulation-based medical training in the MHS is focused on medic and nursing skills, and that large programs are more likely to offer training for advanced providers and GMOs. Potential gaps in the availability of existing training are identified as over 50% of skills included in the nursing, advanced provider, and GMO skill categories are not covered by at least 80% of sites serving those learners. [ABSTRACT FROM AUTHOR]