We describe the incidence of acute chest pain (requiring admission to the emergency department) and the prognosis during two time periods in all patients admitted to the emergency department at Sahlgrenska University Hospital in Göteborg, Sweden, with acute chest pain 1986 and 1987 (period 1) and 1996 and 1997 (period 2). The rate of admission for chest pain/100,000 inhabitants was 4.7/day during period 1 and 5.0/day during period 2. The risk ratio for death adjusted for eight risk factors during period 2 in relation to period 1 was 0.88 (95% CI 0.79-0.97). There was a significant interaction between time period and the severity of the final diagnosis (p=0.02), indicating a greater reduction in mortality among patients with acute myocardial infarction.