OBJECTIVE: To do a cost-effectiveness analysis of the introduction of meningococcal vaccine type C (NeisVac-C(tm)) in Portugal. METHODS: Model: The study compared vaccine with no vaccination for a cohort of 100.000 for lifetime using a Markov model. Scenarios for age of vaccine administration: children with less than one year of age, children with one year of age and children with two years of age. The outcomes measured were avoidable cases, avoidable death, avoidable disability and avoidable years of life lost. RESULTS: For the case base studied the cost per year of life gained (or lost year of prevented life) for the NeisVac-C(tm) was 6372€ for vaccination administer after the first year of life and of 12,635€ for vaccination administer during the first year of life. Difference is explained by the need of two doses of vaccine during the first year of life and only one for the other scenario. These costs includes the cost of vaccines, the effect and consequences of vaccines in the consumption of resources of the health system (hospital, outpatients, medicines, exams, etc.), direct costs for the State other than of the health system (support of the Social Welfare and the deficient ones) and the indirect costs generated by the effect of the disease in the productivity lost by the families in the case of children or of the self in the case of disease while in active labor age. Sensitivity analysis showed the robustness of these values. CONCLUSIONS Compared with other interventions routinely done by the National Health Service the administration of the of the NeisVac-C(tm) it can be considered cost-effective for the Portuguese population.