OBJECTIVES:We tested the hypotheses that the effect of gender on short-term case fatality following a first admission for acute myocardial infarction (AMI) varies with age, and that this effect is offset by differences in the proportion of men and women who survive to reach hospital. BACKGROUND:Evidence is conflicting regarding the effect of gender on prognosis after AMI. METHODS:All 201,114 first AMIs between 1986 and 1995 were studied. Both 30-day and 1-year case fatality were analyzed for the 117,749 patients hospitalized and for all first AMIs, including deaths before hospitalization. The effect of gender and its interaction with age on survival was examined using multivariate modeling. RESULTS:Gender-based differences in survival varied according to age in hospitalized patients, with younger women having higher 30-day case fatality than men (e.g., <55 years, women 6.5% vs. 4.8% men, p < 0.0001). When deaths from first AMI before hospitalization were included in 30-day case fatality, women were less likely to die (adjusted odds ratio 0.9, confidence interval 0.89 to 0.93). Gender was not an independent predictor of one-year survival (p = 0.16). CONCLUSIONS:Female gender increases the probability of surviving to reach hospital, and this outweighs the excess risk of death occurring in younger women following hospitalization. Overall, men have a higher 30-day case fatality than women. Women do not fare worse than men after AMI when age and other factors are taken into account. However, men are more likely to die before hospitalization.