The purpose of this study was to evaluate the possibility to predict in the prehospital phase the occurrence of a life-threatening disease or death among ambulance transported patients with acute chest pain or other symptoms raising any suspicion of an acute coronary syndrome. All patients transported by ambulance during 3 months in the community of Göteborg because of symptoms raising any suspicion of an acute coronary syndrome were included in the study. In all, 930 transports (of 859 patients) fulfilled the inclusion criteria, of which 235 (25.3%) fulfilled the criteria for a life-threatening disease. The overall 30-day mortality was 8.8%, and the 1-year mortality was 18.0%. Independent predictors for a life-threatening disease were a low oxygen saturation on admission of the ambulance crew, patient being clammy on admission of the ambulance crew, a history of myocardial infarction and ST elevation and T-wave inversion on admission to the emergency department. Independent predictors for 30-day mortality were age greater than 70 years, symptoms of dyspnoea, a low oxygen saturation, hypotension and decreased consciousness on admission of the ambulance crew, and ST-depression on electrocardiogram (ECG) on admission to the emergency department. Predictors of 1 year mortality were age greater than 70 years, a history of myocardial infarction, symptoms of dyspnoea, a low oxygen saturation on admission of the ambulance crew and ST-depression, and no sinus rhythm on admission to the emergency department. Among patients with acute chest pain or other symptoms raising any suspicion of an acute coronary syndrome, factors associated with a life-threatening disease and death could be defined. Predictors for the risk of death during the first 30 days were age greater than 70 years, symptoms of dyspnoea, a low oxygen saturation, hypotension and decreased consciousness on admission of the ambulance crew, and ST-depression on ECG on admission to the emergency department.