Summary An outline of the adaptive changes in the immediate postnatal period with particular reference to respiration is given. Only the conditions at normal spontaneous cephalic deliveries have been discussed. The period of time has been limited to 1 to 2 minutes after the delivery as at least half of the adaptive changes seem to have begun within that time. The remainder progress in a decelerating fashion and continue up to some days of age. The key change in the respiratory adaptation to extrauterine life is the aeration of the lungs. Inspiration of the first breath seems to be the main contribution to the aeration of the alveoli; however, there are several possible supporting mechanisms. The need of further studies in this field is emphasized.