Within the SIZ, a national multiïnstitutional clinical research group on cardiopulmonary and cerebral resuscitation (CPCR) has been formed in 1982. The objectives of the studygroup are: Study and improve CPR and cerebral resuscitation post CPR; Optimalise emergency medical services (EMS) in Belgium in this respect. A method to record relevant information on CA was developed and 551 patients were registered on the draft form in 1982. This report outlines the parameters which differ significantly between CPR failures (group I) and initially successful CPR (group II and III); between only initially successful CPR (group II) and longterm survival (group III); and between the different centers in these 551 patients. As the number of patients increases in 1983, this "data bank" information will be valuable both for prognostic prediction of outcome in individual patients post CPR and for guiding improvement in EMS organisation. The study method should allow subsequently the evaluation of future brainresuscitative therapies.