Arterial blood gases, pulmonary mechanics, lung volume measurements and clinical profiles were determined pre and postextubation in 19 infants recovering from respiratory disease. This study evaluated clinical and physiological factors which may be valuable in predicting successful extubation in neonates. Of the 19 patients, 4 required reintubation within 72 h. In this group of patients, the combined profile of low birth weight (1050 g), low gestational age (31 weeks), and high pulmonary resistance (inspiratory 278 cm H2O/L X sec, expiratory 309 cm H2O/L X sec) was significantly different from the 15 patients who were successfully extubated. In addition, lower pHa after extubation was also characteristic of those infants requiring reintubation.