Adenovirus vaccines have controlled acute respiratory disease (ARD) in military recruits since 1971. Vaccine production, however, ceased and new facilities are required. We assessed whether reacquiring and using vaccines in naval recruits is cost-effective. Three policy options were evaluated: no vaccination, seasonal vaccination, and year-round vaccination. Morbidity (outpatient and inpatient), illness costs (medical and lost training), and vaccine program costs (start-up, acquisition, and distribution) were modeled using a decision-analytic method. Results were based on a cohort of 49,079 annual trainees, a winter vaccine-preventable ARD rate of 2.6 cases per 100 person-weeks, a summer incidence rate at 10% of the winter rate, a hospitalization rate of 7.6%, and a production facility costing US$12 million. Compared to no vaccination, seasonal vaccination prevented 4,015 cases and saved $2.8 million per year. Year-round vaccination prevented 4,555 cases and saved $2.6 million. Reacquiring and using adenovirus vaccines seasonally or year-round saves money and averts suffering.