75 out of 77 children surviving IRDS with the aid of intermittent positive pressure ventilation have been followed up by age 2.6-7.6 years together with 68 matched controls. The morbidity of lower respiratory tract illnesses was significantly higher in IRDS survivors than in controls affecting a total of 48%, half whom were admitted to hospital on at least on occasion. Only 3 IRDS survivors had pneumonias beyound their third year, however. One child suffered from a moderate stridor due to a partial laryngeal stenosis and one from some dyspnoea at function caused by broncho-pulmonary dysplasia. Thoracic X-ray changes were found significantly more often and more marked in IRDS survivors but on the whole the changes were discrete. Neither the occurrence of pneumonia nor X-ray changes in the IRDS survivors were statistically relatable to a number of neonatal or therapeutical characteristics. Measurements of heart volume, respiratory frequency, oxygen saturation and acid-base values did not differ between the groups. Ventilated IRDS survivors, even with some degree of radiographic demonstrable residua, thus seem to have a good long-term prognosis with regard to lung function, irrespective of a preliminary high morbidity of lower respiratory tract illnesses.