An unusual manifestation of asthma occurred in 11 children who had chronic cough and no wheezing. Initial, routine pulmonary function tests gave normal results in most cases. The diagnosis of asthma was confirmed by an exercise provocation test in ten children and/or a successful therapeutic trial with bronchodilators. The asthma in these cases had previously remained undiagnosed (hidden) for years, during which time the patients were treated unsuccessfully with antibiotics, antitussives, and antihistamines. Earlier diagnosis of this asthmatic illness assisted by exercise provocation testing will result in more effective management.