Five years' experience with mechanical ventilation of 204 neonates with similar degrees of respiratory failure is described. The survival of these infants is discussed in relation to clinical diagnosis, hospital of birth, birth weight and age at initiation of ventilation. Complications encountered during mechanical ventilation of the infants are discussed. The results of the overall experience suggest that intermittent positive-pressure ventilation (IPPV/I) improves the rate of survival of infants with respiratory failure, and that complications of mechanical ventilation need not be excessive.