OBJECTIVES: To investigate sex differences in reaching diagnosis, medical management and case fatality (CF) in acute myocardial infarction (AMI) in the population aged 35-64 years in northern Sweden. METHODS: Within the framework of the World Health Organization Multinational Monitoring of Trends and Determinants in Cardiovascular Diseases (MONICA) Project, definite AMI was monitored in people aged 35-64 years from 1989 through 1995 (target population 510 000 in 1991). SETTING: In a population based coronary register, all coronary events were recorded in nine hospitals in 1989-95. RESULTS: The number of events included in the definite coronary myocardial infarction register was 2483 men and 669 women. On admission, a higher proportion of men with definite AMI had chest pain or ECG changes typical for AMI (P