Decisions regarding the introduction of influenza immunization in healthy children require an accurate evaluation of influenza disease burden not only in the inpatient but also in the outpatient setting. We prospectively examined the impact of virologically confirmed influenza in 1462 outpatient children (> or = 6 months to < 14 years) and their families, during two consecutive influenza seasons. Influenza was documented in 573/1462 (39%) outpatients with febrile respiratory illness and accounted for 13.5% of all outpatient visits during the 14 weeks of each season. Acute otitis media (AOM) was the most common complication (18.5%) and about 40% of influenza positive patients received antibiotics. AOM and antibiotic use were more common in children younger than 5 years of age who accounted for 58% of all patients. For each child sick with influenza a mean of 1.34 workdays were lost by the parents. Family members of influenza positive children were more likely to develop a secondary respiratory illness and to require medical visits and antibiotic prescriptions. Influenza is associated with a heavy morbidity burden in the community that may be reduced considerably with the implementation of immunization in children younger than 5 years of age.