We retrospectively reviewed the manifestations of influenza A2 in 83 hospitalized young children. Our purpose was to define the spectrum of clinical illness in this age group. Findings included fever (91%), vomiting or diarrhea (49%), pharyngitis (34%), pneumonitis (29%), otitis media (24%), conjunctivitis (13%), croup (13%), and bronchiolitis (6%). Neuromuscular manifestations occurred in 16 patients (19%) and included seizures, apnea, opisthotonos, and myositis. Three children had cerebrospinal fluid pleocytosis. Children younger than 3 months of age had fever less often and gastrointestinal symptoms more often than older children. Threee children died of progressive pneumonitis. We conclude that influenza A2 may cause a wide range of respiratory and neurologic findings in infancy and early childhood.