The aim of this report is to establish recommendations for reviewing, reporting, and conducting research during the post-resuscitation period in hospital. It defines data that are needed for research and more specialised registries and therefore supplements the recently updated Utstein template for resuscitation registries. The updated Utstein template and the out-of-hospital "Chain of Survival" describe factors of importance for successful resuscitation up until return of spontaneous circulation (ROSC). Several factors in the in-hospital phase after ROSC are also likely to affect the ultimate outcome of the patient. Large differences in survival to hospital discharge for patients admitted alive are reported between hospitals. Therapeutic hypothermia has been demonstrated to improve the outcome, and other factors such as blood glucose, haemodynamics, ventilatory support, etc., might also influence the result. No generally accepted, scientifically based protocol exists for the post-resuscitation period in hospital, other than general brain-oriented intensive care. There is little published information on this in-hospital phase. This statement is the result of a scientific consensus development process started as a symposium by a task force at the Utstein Abbey, Norway, in September 2003. Suggested data are defined as core and supplementary and include the following categories: pre-arrest co-morbidity and functional status, cause of death, patients' quality of life, in-hospital system factors, investigations and treatment, and physiological data at various time points during the first three days after admission. It is hoped that the publication of these recommendations will encourage research into the in-hospital post-resuscitation phase, which we propose should be included in the chain-of-survival as a fifth ring. Following these recommendations should enable better understanding of the impact of different in-hospital treatment strategies on outcome.