We analyzed the cost-effectiveness of hepatitis A vaccination regimens using a mathematical simulation model. Passive immunization and two active vaccination strategies (with and without prior screening) were compared with "doing nothing." Hepatitis A antibodies were determined in 2,325 Dutch marines; other input data were retrieved from published and unpublished sources. The prevalence of hepatitis A antibody was 14%. Screening before vaccination was identified as appropriate at a prevalence > 20%. Passive immunization was the cheapest prevention for a single 6-month deployment per 10 years. The inactivated vaccine containing 1,440 enzyme-linked immunosorbent assay units without prior screening was identified as the best option for more frequent deployments. It was cost-saving with two or more missions per 10 years. A 5.3% hepatitis A attack rate validated the investment for this policy. Overall, immunization with inactivated hepatitis A vaccine without prior screening proved to be the optimum strategy for troops at regular risk.