OBJECTIVES: To assess the cost effectiveness of a meningococcal serogroup C conjugate vaccination campaign in 0-17 year olds. DESIGN: Cost effectiveness analysis from the perspective of the healthcare provider. SETTING: England and Wales. MAIN OUTCOME MEASURE: Cost per life year saved. RESULTS: In 1998-9, immediately before the introduction of meningococcal C vaccination, the burden of serogroup C disease was considerable, with an estimated 1137 cases in people aged 0-17 years and at least 72 deaths. The vaccination campaign is estimated to have cost between 126m pound sterling ($180m, 207m) and 241 pound sterling 3m, 395m), depending on the price of the vaccine. Under base case assumptions the cost per life year saved from the vaccination campaign is estimated to be 6259 pound sterling. School based vaccination was more cost effective than general practice based vaccination because of lower delivery costs. Immunisation of infants aged under 1 year was the least cost effective component of the campaign because, although this maximises the life years gained, the three dose schedule required is more expensive than other methods of delivery. Estimates of the cost per life year saved were sensitive to assumptions on the future incidence of disease and the case fatality ratio. CONCLUSIONS: Meningococcal C vaccination is likely to be more cost effective in all age groups when the incidence of disease is high. It is also more cost effective when given to children aged 1-4 (by general practitioners) and to children and young people aged 5-17 years at school than when administered to infants under 12 months of age or young people aged 16-17 years who are not at school.