A 3-week-old baby, suffering from whooping cough with severe attacks of apnoea and hypoxia, was treated by nasal CPAP with a positive airway pressure of about 5 cm H2O. The respiration improved rapidly and the transcutaneous oxygen tension increased to a normal level. The treatment was carried on for 7 days and discontinued gradually in the course of 3 days. The child was also treated with pertussis immunoglobulin and erythromycin. The CPAP system employed is easily and rapidly applied and allows normal nursing of the child during the treatment and manual lung physiotherapy in upright position. The treatment probably proved lifesaving.