Chronic obstructive bronchitis with inadequate response to inhaled steroid and bronchodilator therapy is a rather rare disorder in children. Persistence of an adenoviral infection has been described as a possible cause of unremitting airway obstruction. We studied a group of 11 children with the clinical feature of chronic bronchial obstruction. A high-resolution computed tomography (HR-CT) scan was performed and typically showed hyperinflation and ground-glass-like opacities. All children underwent either bronchoscopic transbronchial or open lung biopsy. Biopsy specimens were stained with monoclonal antibodies detecting adenoviral antigen and analyzed by light-microscopy. Bronchoalveolar lavage (BAL) fluid was cultured for adenovirus, and antigen detection tests were performed. While some children had a history of proven adenoviral infection at the onset of their disease, in none of the cases could a persistence of adenovirus be shown. We conclude that adenoviral infection might act as a starter of chronic obstructive bronchitis in children, but that pathogenetic mechanisms other than persistent infection must be responsible for the chronicity of the disease.