Sixty-six patients more than 30 days and less thant 16 years of age suffering an unexpected cardiac arrest in an 18-month period were included in a study of resuscitative measures in children. Six children survived to be discharged from hospital. Respiratory disease accounted for most (29%) of the cardiac arrests, but it also had the most favourable prognosis, 21% of the 19 patients surviving. None of the patients survived whose cardiac arrest was secondary to sepsis or trauma, even when the resuscitative efforts were initially successful. Only 1 of the 41 patients who had a cardiac arrest outside of hospital survived, and only 1 of the 34 patients who presented with asystole survived, and then with considerable damage to the central nervous system. The interval between cardiac arrest and application of basic life support was substantially shorter among the survivors. Also, most of the survivors did not present with asystole. The results of this study suggest that survival among resuscitated children is no better than that among adults but can be improved with early recognition and monitoring of children at risk. earlier application of basic and advanced life support, improved education of medical and lay personnel, and further research into pediatric resuscitative techniques.