Aim: To study the outcome in early adulthood for children with early asthma symptoms and to analyse the factors associated with current asthma. Methods: In a prospective study, we have re- investigated 89/101 children who were hospitalized before the age of two years due to wheezing. The children were investigated using a questionnaire and allergy and bronchial hyperresponsiveness tests at the age of 17- 20 years and compared with age- matched controls. Results: In the cohort, 43% had had asthma symptoms in the preceding 12 months compared with 15% in the control group. The strongest risk factors for asthma were current allergy, bronchial hyper- responsiveness and female gender. Female gender and passive smoking in infancy were independent infantile risk factors. In addition to female gender, two pathways led to current asthma: an allergic pathway from family atopy via the development of allergy and another pathway from early passive smoking via hyperresponsiveness and active smoking. Conclusion: In children with early wheezing disorder, current allergy, bronchial hyper- responsiveness and female gender were the strongest risk factors for asthma in early adulthood, while female gender and passive smoking in infancy were independent infantile risk factors. The effects of early passive smoking persist longer than previously reported. Aim: To study the outcome in early adulthood for children with early asthma symptoms and to analyze the factors associated with current asthma. Methods: In a prospective study, we have re- examined 89/101 children who were hospitalized before the age of two years The children were investigated using the questionnaire and allergy and bronchial hyperresponsiveness tests at the age of 17- 20 years and compared with age-matched controls. Results: In the cohort, 43% had had asthma symptoms in the previous 12 months compared with 15% in the control group. The strongest risk factors for asthma were current allergy, bronchial hyper-responsiveness and female gender. Female gender and passive smoking in infancy were independent infantile risk factors. In addition to female gender, two pathways led to current asthma: an allergic pathway from family atopy via the development of allergy and another pathway from early passive smoking via hyperresponsiveness and active smoking. Conclusion: In children with early wheezing disorder, current allergy, bronchial hyper-responsiveness and female gender were the strongest risk factors for asthma in early adulthood, while female gender and passive smoking in infancy were independent infantile risk factors. The effects of early passive smoking persist longer than previously reported.