Bronchopulmonary dysplasia is a serious chronic lung disease of infancy but despite numerous problems such as poor growth, recurrent lower respiratory tract infections, and cor pulmonale, steady improvement and recovery may generally be expected. We report four infants with bronchopulmonary dysplasia in whom the cardiopulmonary course did not show the usual steady improvement. Each infant was found to have an unsuspected cardiopulmonary lesion in addition to lung disease: two had congenital heart disease and two upper airway obstruction. Three improved after surgical intervention but one patient died immediately after this. Persistent right ventricular hypertrophy in patients with bronchopulmonary dysplasia maintained on supplemental oxygen, and a particularly slow rate of recovery from the need for supplemental oxygen are markers that should lead to evaluation for coexisting cardiopulmonary abnormalities.