This study was conducted to establish the attack rate, mortality rate and 28-day case-fatality rates of acute myocardial infarction (AMI) occurring in Girona, Spain, between October 1987 and September 1988. The study was carried out using a population register of AMI, and took place in one central hospital, and eight county hospitals in Girona (in the autonomous community of Catalonia, northeast Spain). Subjects comprised 222 fatal cases selected from 4069 death certificates, and 210 non-fatal cases from hospital records, among subjects aged between 25 and 74 years (reference population 263,778). The age standardized attack rate was 105.6 per 100,000 inhabitants in the age group 35-64 (193.6 in men and 17.6 in women). The age standardized mortality rate was 36.3 per 100,000 inhabitants in the age group 35-64 (63.1 among men and 9.9 among women). The age standardized 28-day case-fatality was 34.6% in men and 50.1% in women in this same age group. Attack and mortality rates of AMI in a region of Spain are presented for the first time. These rates are lower than in other developed countries, nevertheless the 28-day case-fatality is similar to that of these countries.