The relatively high incidence of Eaton agent infection in military personnel and their dependents is probably the most striking revelation of this study. Review of the roentgenograms of 34 young adults and 4 children with Eaton agent pneumonia revealed no characteristic diagnostic features. The pulmonary [See figure in the PDF file] infiltrate is bronchopneumonic in type and clears without residual pleural or parenchymal scarring. Hilar lymphadenopathy is not too common and pleural effusion is so rare as to suggest a different diagnosis. Response to broad spectrum antibiotics was satisfactory and there were no complications. No biopsy or autopsy material was available for study.