Adenoviruses, particularly types 4 and 7, are associated with febrile respiratory illness (FRI) outbreaks in US military basic trainees. Vaccines against these two serotypes controlled FRI in basic trainees until production ceased in the mid-1990s. After contracting a new manufacturer, adenovirus vaccination of military basic trainees resumed in 2011. The purpose of this dissertation was to assess the cost-effectiveness of using the new adenovirus type 4 and type 7 vaccines for the prevention of FRI in US military basic trainees from the perspective of each military branch. Two decision tree models comparing adenovirus vaccination to no adenovirus vaccination were used for this dissertation. The first model is similar to previous models used to assess the cost-effectiveness of the adenovirus vaccine in the military, where the outcome is number of FRI hospitalizations prevented. The second model created for this dissertation used information gathered from published literature and conversations with experts on the adenovirus vaccine. The outcome for the second model was number of training days lost (TDL) averted. Results from part I indicated that adenovirus vaccination of basic trainees was cost-effective as measured by FRI hospitalizations prevented in all US military service branches but the Coast Guard. The model showed that reintroducing the adenovirus vaccine to basic trainees saved the Army $5.8 million, the Navy, $1 million, the Marine Corps, $238,000, and the Air Force, $5.2 million, annually. In addition, adenovirus vaccination prevented 1,221, 543, 317, 677 cases of FRI hospitalization annually in the Army, Navy, Marine Corps, and Air Force respectively. In part II of this study, adenovirus vaccination of basic trainees was the dominant strategy as measured by TDL averted in all US military service branches but the Marine Corps and the Coast Guard. Results indicate that it would cost approximately $37.63 and $563.78 per TDL averted for the Marine Corps and Coast Guard respectively. Both models used for this dissertation provide evidence supporting the cost-effectiveness of using the adenovirus vaccine in US basic trainees in all services but the Coast Guard. / text