Background: Care of trauma casualties in an austere environment presents many challenges, particularly when evacuation is not immediately available. Man-packable medical supplies may be consumed by a single casualty, and resupply may not be possible before evacuation, particularly during prolonged field care scenarios. We hypothesized that unmanned aerial drones could successfully deliver life-sustaining medical supplies to a remote, denied environment where vehicle or foot traffic is impossible or impractical. Methods: Using an unmanned, rotary- wing drone, we simulated delivery of a customizable, 4.5kg load of medical equipment, including tourniquets, dressings, analgesics, and blood products. A simulated casualty was positioned in a remote area. The flight was preprogrammed on the basis of grid coordinates and flew on autopilot beyond visual range; data (altitude, flight time, route) were recorded live by high-altitude Shadow drone. Delivery time was compared to the known US military standards for traversing uneven topography by foot or wheeled vehicle. Results: Four flights were performed. Data are given as mean (± standard deviation). Time from launch to delivery was 20.77 ± 0.05 minutes (cruise speed, 34.03 ± 0.15 km/h; mean range, 12.27 ± 0.07 km). Medical supplies were delivered successfully within 1m of the target. The drone successfully returned to the starting point every flight. Resupply by foot would take 5.1 hours with an average speed of 2.4km/h and 61.35 minutes, with an average speed of 12 km/h for a wheeled vehicle, if a rudimentary road existed. Conclusion: Use of unmanned drones is feasible for delivery of life-saving medical supplies in austere environments. Drones repeatedly and accurately delivered medical supplies faster than other methods without additional risk to personnel or manned airframe. This technology may have benefit for austere care of military and civilian casualties.