OBJECTIVE: To estimate the cost-utility of universal vaccination of infants with four doses of a combined 9-valent conjugated pneumococcal / 6-valent outer membrane vesicle meningococcal B/C vaccine in the Netherlands, from a societal perspective. METHODS: A decision analysis model is employed to estimate the health outcomes and costs of the vaccination program. Data were derived from the Netherlands Reference Laboratory for Bacterial Meningitis, PRISMANT Healthcare, national and international literature, and an expert panel. Direct costs and productivity costs (friction cost method) are considered. Future costs and QALYs are discounted at 4%. Cost-utility is expressed as net costs (in 1998 €) per QALY gained. For the baseline, a vaccine dose price of € 20 and vaccine dose administration cost of € 5 are assumed. The study fully corresponds with the Dutch guidelines for pharmacoeconomic research. RESULTS: The vaccination program is estimated to cost € 18,741,600, to prevent 27 deaths and 16 severe sequelae (e.g. seizures, spasticity, and mental retardation), and to avoid € 7,546,600 in expenses per year. It would render 735 QALYs per year at a cost-utility of €15,200 per QALY. The break-even dose price of the vaccine is € 5.7. These results are sensitive to the vaccine price, the vaccine effectiveness, and the vaccine coverage against other meningococcal serosubtypes and pneumococcal serotypes. Excluding the productivity costs has a limited influence. CONCLUSIONS: The combination vaccine has not only a favourable cost-utility ratio when compared to other vaccines, but also averts a significant number of deaths and severe sequelae. Therefore it would be a promising candidate for national immunization programs.