Trichomonas vaginalis was isolated from the respiratory tracts of two infants with respiratory disease. Bacterial and viral cultures of tracheal aspirates and nasopharyngeal specimens did not detect bacterial pathogens or viruses; however, T vaginalis was found to be present in inoculated cell cultures. Both infants were delivered vaginally by mothers with known previous episodes of T vaginalis infection. The possibility that this organism may, on occasion, cause respiratory tract disease needs further evaluation.