We applied a reverse transcription (RT)-PCR assay for influenza A virus to combined nasal wash-throat swab specimens previously obtained from an outpatient pediatric population with acute respiratory illness during concurrent epidemics of influenza A virus and respiratory syncytial virus, The results of the RT-PCR assay were compared with those previously reported with virus cultivation and commercially available rapid diagnostic kits (E. A. Dominguez, L. H. Taber, and R. B. Couch, J. Clin, Microbiol. 31:2286-2290, 1993). With virus cultivation as the ''gold standard,'' the RT-PCR assay had a sensitivity, specificity, and efficiency of 95, 98, and 97%, respectively, compared with 75, 100, and 93%, respectively, for the best diagnostic kit (Becton Dickinson Directigen). RT-PCR is an effective alternative to virus isolation for the detection of influenza A virus in clinical specimens.