BACKGROUND: A large number of patients who call for an ambulance because of acute chest pain have an acute ischaemic event, but some do not. AIM. To relate the ambulance despatcher's estimated severity of pain and presence of associated symptoms, in patients who call for an ambulance because of acute chest pain, to whether they develop acute myocardial infarction (AMI) and to the risk of early death. PATIENTS: All those with acute chest pain who contacted the despatch centre in Göteborg over a 2-month period. RESULTS: In all, 503 patients fulfilled the inclusion criteria. Patients judged as having severe chest pain (68%) developed AMI during the first 3 days in hospital on 26% of occasions as compared with 13% among patients judged as having only vague chest pain (P = 0.0004). The difference was less marked among the elderly and women. The presence of any of the following associated symptoms, dyspnoea, nausea, vertigo, cold sweat or syncope, tended to be associated with a higher infarction rate (24%) than if none of these symptoms was present (17%, P = 0.06). Mortality during the pre-hospital and the hospital phase was not associated with the estimated severity of pain or the presence of associated symptoms. CONCLUSIONS: The despatcher's estimation of the severity of pain and the presence of associated symptoms appears to be associated with the development of AMI but not with early mortality.