OBJECTIVES: Vaccination is established as one of the most effective methods to prevent influenza and reduce the related social and economic burden. The objectives of this study were to estimate the cost-effectiveness ratios of using the live attenuated influenza vaccine (LAIV), indicated for children aged 2 to 18 years, as well as evaluate the impact of herd immunity in the non-vaccinated population. METHODS: An adaptable and flexible dynamic transmission model, stratified by age, was used to simulate the impact of influenza infection, with a time horizon of 5 years. This study was conducted in a payer perspective and was adapted to the Portuguese setting, as all data related to demographics and costs belonged to Portuguese sources.  RESULTS: In the base case scenario, two different childhood vaccination policies were compared: use the trivalent influenza vaccine (TIV) currently in the market or use the LAIV, both for healthy children population. For the same number of vaccinated individuals, the LAIV achieved a reduction in the incidence of influenza and in the number of deaths due to influenza mostly among the elderly, when compared with the results obtained with TIV. The incremental cost-effectiveness ratios obtained were 7,448 and 8,527€/QALY, for a vaccination coverage of 25 and 75%, respectively. The net monetary benefit obtained was positive.  CONCLUSIONS: The results showed that the strategy for influenza vaccination using LAIV in children is cost-effective as it reduces the costs related to influenza infection and has a positive impact in the Portuguese healthcare from direct and indirect protection in the community.