Prevention of Early Asthma in Kids (PEAK) began recruitment in January 2001 and evaluated whether administering inhaled corticosteroids to 24-48 month old children at risk of developing asthma prevented the development of persistent asthma. All subjects were expected to be randomized prior to December 2001 with study completion by September 2004. The study was a double blind, randomized, placebo controlled, parallel comparison of inhaled fluticasone to placebo. There was a four week run-in period to qualify and characterize children. A total of 285 children were randomized to one of two treatment groups; one receiving active treatment, the other placebo. The study was based on a continuous treatment schedule for a period of twenty-four months, followed by an observation period of one year during which the main outcomes were assessed. The primary outcome measure was the number of asthma-free days. Secondary outcomes included number of exacerbations, use of asthma medications, and lung function. There were three specific objectives of the study: 1) To assess if chronic therapy with inhaled corticosteroids initiated in children four years or less at high risk of developing asthma can prevent the development of significant asthma at four to six years of age, 2) To determine if asthma therapy as described above can prevent both losses in lung function and the development of bronchial hyperresponsiveness (BHR) associated with early onset asthma, and 3) To assess potential side effects that may be associated with long term use of inhaled steroids in early life. PEAK study outcomes were presented at the 2005 annual meetings of the American Academy of Allergy, Asthma, and Immunology and the American Thoracic Society. A manuscript has been submitted for publication by the New England Journal of Medicine.