We describe the development of pediatric pulmonology in North America, from its rudimentary beginning in the early part of the 20th century. Milestones in the history of lung diseases affecting children, such as tuberculosis, cystic fibrosis, asthma, and neonatal lung disease, are discussed. Finally, maturation into a subspecialty recognized by the American Board of Pediatrics is described. An understanding of the function of the respiratory system and descriptions of disorders that affect the lung date back to antiquity. This historical perspective of the discipline of pediatric pulmonology begins in the 1800s. At the end of the 19th century, when the American Pediatric Society (APS) was formed, the main scourges of children were infectious diseases, including diarrhea, diphtheria, tuberculosis, scarlet fever, pneumonia and empyema, typhoid fever, influenza, and "hereditary" syphilis (1). Concepts of public hygiene, proper diet, and fluid replacement therapy were rudimentary or absent. The only laboratory tools available were pathologic histology and morphologic bacteriology. Notably, only two of the 43 founding members of the APS limited their practice to pediatrics: L. Emmett Holt (New York) and Isaac Love (St. Louis) (2).The following is a very truncated view of some of the APS meetings and the topics discussed that pertained to pulmonology. The first meeting of the APS was held in 1889 in Washington, DC, and was attended by 25 members who read 27 papers (1). Many of the papers were devoted to infant feeding, but there were presentations on pneumothorax and lung expansion, tuberculosis, meningitis, scarlet fever, neona-