Background.The etiology of acute myringitis remains controversial although it is usually encountered in connection with acute otitis media (AOM). In most cases of acute myringitis a bacterial pathogen has been detected in the middle ear fluid, but the role of respiratory viruses has remained unclear. Our objective was to investigate the etiologic role of viruses in the pathogenesis of acute bullous and hemorrhagic myringitis in children <2 years of age.Methods.A prospective longitudinal cohort study of 2028 children ages 7 to 24 months in primary care in the Finnish Otitis Media Vaccine Trial. Nasopharyngeal aspirate (NPA) and middle ear fluid (MEF) samples taken at the time of the diagnosis were examined by a time-resolved fluoroimmunoassay for antigen detection of adenoviruses; influenza viruses A and B; parainfluenza viruses 1, 2 and 3; and respiratory syncytial virus and by reverse transcription polymerase chain reaction for human rhinovirus and human enterovirus.Results.Eighty-two children with bullous myringitis and 37 children with hemorrhagic myringitis were diagnosed during the 18-month follow-up period. In bullous myringitis a respiratory virus was detected in 70% of NPA samples and in 27% of MEF samples. In hemorrhagic myringitis 57% of NPA samples and 28% of MEF samples were virus-positive. The viral distribution was similar to that of AOM (virus positive 64% of NPA and 37% of MEF).Conclusions.We could not confirm any specific respiratory virus to be the etiologic agent in acute myringitis. The etiology of acute myringitis is similar to that of AOM in children <2 years of age.