Introduction and objectives: Myocardial infarction (MI) incidence and case fatality trends are highly informative but relatively untested at the population level. The objective of this work was to estimate MI incidence and case fatality in the Girona population aged 35-74 years, and to determine their 30-year trends (1990-2019). Methods: The REGICOR (Girona Heart Registry) monitored MI incidence and case fatality rates from 1990 to 2008. For the period 2008 to 2019, we linked discharges from Girona hospitals (n = 4 974 977) and mortality registry (n = 70 405) during this period. Our linkage algorithm selected key MI diagnostic codes and removed duplicates. Estimates from the linkage algorithm and the REGICOR registry were compared using chi-square tests for overlapping years (2008-2009). We estimated the annual percent change (APC) of standardized MI incidence and 28-day case fatality, and analyzed their trends using joinpoint regression. Results: MI incidence and case fatality estimates were similar in the linkage algorithm and the REGICOR registry. We observed significant decreasing trends in the incidence of MI. The trend was APC, -0.96% (95% confidence interval (95%CI), -1.4 to -0.53) in women from 1990 to 2019 and -4.2% (95%CI, -5.5 to -3.0) in men from 1994 to 2019. The largest decrease in case fatality was -3.8% (95%CI, -5.1 to -2.5) from 1995 to 2003 in women and -2.4% (95%CI, -2.9 to -1.9) from 1995 to 2004 in men, mainly due to prehospital case fatality declines: -1.8% (95%CI, -2.6 to -1.1) in men and -3.2% (95%CI, -4.6 to -1.8) in women. Conclusions: In Girona, MI incidence and case fatality decreased between 1990 and 2019. The incidence showed a slow but continuous decrease while case fatality only stabilized in the last decade, particularly in women.