Influenza vaccination of children 6-23 months of age is recommended in the United States and Canada because of high rates of influenza-associated hospitalisations, but few other countries have adopted similar policies. Most children with influenza are treated in the primary care setting, and the cost-effectiveness of influenza vaccination of children has not been fully established. We used a decision analysis model to assess the cost-effectiveness of influenza vaccination of children 6 months to 13 years of age in Finland. The analyses were based on comprehensive clinical data on virologically confirmed influenza infections, hospital medical records, and national registers. We estimated the impact of influenza on outpatient and hospitalised children and their families, and performed the analyses from the health care provider and societal perspective. Influenza vaccination resulted in savings in all programs including children <or=13 years of age from both the health care provider and societal perspective. Investing 1.7 million euros in vaccination of children <5 years of age yielded savings of 2.7 million euros in health care costs. From the health care provider perspective, the savings per vaccinated child ranged between 5.7 and 12.6 euros in any program including children up to 13 years of age. The vaccination was cost saving in all age groups even with assumed vaccine efficacy of 60%. The results show that influenza vaccination would be cost saving in all children <or=13 years of age in Finland, which advocates reconsideration of the current influenza vaccine recommendations in all countries.