Outcome after prehospital cardiac arrest was examined in the EMS system of Bonn, a midsized urban community, and presented according to the Utstein style. The data were collected from January 1st, 1989 to December 31st, 1992 by the Bonn-north ALS unit, which serves 240,000 residents. Fifty-six patients suffered from cardiac arrest of non-cardiac aetiology and were excluded; 464 patients were resuscitated after cardiac arrest of presumed cardiac aetiology (incidence of CPR attempts: 48.33 per year/100,000 population). The collapse was unwitnessed, bystander witnessed or EMS personnel witnessed in 178, 214 or 72 patients, respectively. In these subgroups discharge rates and 1-year survival accounted for 7.3% (4.5%), 22.9% (15.9%) and 16.7% (11.1%), respectively. Thirty-four patients were discharged without neurological deficits (cerebral performance category 1: CPC 1), 22 and nine patients scored CPC 2 or CPC 3, respectively. Nine patients were comatose (CPC 4) when they were discharged and remained in this state until they died. Of the 50 1-year survivors 35 lived without neurological deficit, eight demonstrated mild (CPC 2) and five severe (CPC 3) cerebral disability at 1-year after resuscitation, and, finally, two patients remained comatose for more than 1 year. The Utstein template recommends the selection of patients who were found in VF after bystander witnessed collapse. In our cohort 118 patients met these criteria. Of them 41 (35%) could be discharged from hospital and 28 (24%) lived more than 1 year. The comparison of our data with those from double-response EMS systems of other communities revealed that, in midsized urban and suburban communities the highest discharging rates could be achieved. Our study demonstrated that survival depends crucially on short response intervals and life support which will be performed by well-trained emergency technicians, paramedics and physicians.