Cardiorespirographic studies were performed in 11 prematures with episodes of apnea and bradycardia (gestational age: x = 31 weeks, birth weight: x = 1390g). Total registration time was 90 h; 45 h during spontaneous breathing, 45 h during CPAP-treatment. Episodes of bradycardia occured three times more frequently than apnea. The frequency of apnea and bradycardia, the duration of bradycardia and the deceleration area were significantly reduced during CPAP-therapy, whilst the duration of apnea was not influenced. Estimation of deceleration areas as compared to measurements of bradycardia duration offers no further clinical advantage. Respiratory monitoring by impedance has to be supplemental or even replaced by beat-to-beat heart rate monitoring. Cardiorespirography allows assessment of frequency and degree of pathophysiological changes in heart rate and breathing patterns and should be supplemented by transcutaneous oxygen measurements.