Although there are many studies on the short-term outcome of bronchiolitis or early childhood wheezing, there are limited data on these children as they enter adulthood. This longitudinal study from Finland followed 127 children hospitalized for bronchiolitis or pneumonia in the first 24 months of life to age 18 to 21 years. They were compared with a control group of individuals without a family history of atopy, followed up from birth. Asthma was significantly more common in the young adults who had been hospitalized for respiratory infections as infants, whereas there was no difference in atopy. The increased risk of asthma appears to persist until adulthood after bronchiolitis in infancy.