Nine children who survived the development of Wilson-Mikity (W-M) syndrome were studied at a mean age of 7.6 +/- 0.3 years. Persistent respiratory symptoms during the year preceding the study were present in one child. Pulmonary function studies demonstrated a significant degree of airway obstruction in 3 children. Positive methacholine challenge was observed in 6 children indicating bronchial hyperreactivity. Abnormal chest radiographs were present in 3 children. One showed the characteristic appearances of asthma with air trapping, bronchial wall thickening and redistribution of pulmonary vessels. The other child showed minimal residual peribronchial thickening and the third child had normal lungs, but a rather prominent pulmonary artery segment. Echocardiographic studies revealed enlarged right ventricular cavity in 2 children. However, the pre-ejection period and the systolic time intervals were all within normal limits. It appears that unlike patients with bronchopulmonary dysplasia survivors of W-M syndrome have a good prognosis.