A clinically useful diagnostic method has been developed for detecting and quantitating periods of apnea in pediatric patients. This procedure, called the pediatric pneumogram, permits the continuous recording on magnetic tape, for periods of up to 13 hours, of the respiratory pattern of infants utilizing an impedance technique. This test has been employed successfully in a variety of infants to evaluate respiratory activity and has permitted the objective documentation of apneic and cyanotic episodes, as well as an assessment of the effectiveness of therapy.