OBJECTIVES: To estimate the cost-effectiveness of the Advisory Committee on Immunization Practices (ACIP) recommended schedule of adult immunizations in the US. METHODS: A cost-effectiveness calculator was constructed for the ACIP recommended adult immunization schedule and included the following vaccination strategies (ages in years): Influenza (annually, age 50+), Hepatitis A/B (Hep A/B, college students age 18), Human Papillomavirus (HPV, women age 18-26), Pneumococcal Polysaccharide (PPV, age 50+), Tetanus-Diphtheria acellular Pertussis (Tdap, age 20), Varicella (age 20+), and Zoster (age 60+).  Per-person estimates of discounted costs (2008$) and quality adjusted life years (QALYs) were derived from existing cost-effectiveness studies of target vaccinations vs. no vaccination.  Two approaches were taken – cross-sectional and longitudinal.  In the cross-sectional approach, members of a hypothetical US-age-weighted cohort were assumed to receive the vaccinations for which they were eligible in a single year, lifetime incremental costs and QALYs were summed over the cohort, and an aggregate ICER calculated.  In the longitudinal approach, incremental costs and QALYs from existing studies were applied to a cohort of 18 year-olds at the appropriate age for each vaccine; costs and QALYs were discounted to the present, summed, and an aggregate incremental cost-effectiveness ratio (ICER) was calculated. RESULTS: Estimated ICERs were $7300/QALY and $8000/QALY for the cross-sectional and longitudinal approaches, respectively.  Both approaches are influenced by inclusion of influenza vaccinations; however excluding influenza still results in cost-effective ICERs (below $30,000/QALY (cross-sectional) and below $20,000/QALY (longitudinal)).  In contrast, removing HPV, Hep A/B, PPV, Tdap, Varicella, or Zoster individually from the immunization schedule does not markedly alter the ICER. Advancing the cohort starting age from 18 to 65 years decreases the ICER to $5000/QALY for the longitudinal approach. CONCLUSIONS: Independent of the analytic approach, adult immunization according to the current ACIP schedule is cost effective.