Background: Previous reports have generally shown lower utilization of hospital resources and lower survival in women than men with acute myocardial infarction. However, to our knowledge, no reports have described the influence of payer status on the treatment and outcome of women and men with acute myocardial infarction. Methods: Baseline and clinical presenting characteristics, utilization of hospital resources, and subsequent clinical outcome were ascertained among 327 040 women and men enrolled in a national registry of myocardial infarction from June 1, 1994, to January 31, 1997. Separate Cox regression analyses were performed for Medicare, Medicaid, health maintenance organizations, and commercial payer groups to ascertain variables that were predictive of mortality in the study population. Results: After adjustment for differences in age and other baseline and presenting characteristics, women were significantly more likely than men to die in the hospital (hazard ratio, 1.13; 95% confidence interval, 1.10-1.16), and this difference was greatest among women with health maintenance organization and commercial insurance (hazard ratios, 1.30 and 1.29, respectively), and least among women with Medicare (hazard ratio, 1.07). However, after adjustment for the additional effect on short-term survival of sex differences in the utilization of both pharmacologic treatments administered within the first 24 hours and invasive cardiac procedures, the mortality difference observed for women and men further diminished (hazard ratio, 1.08; 95% confidence interval, 1.05-1.10). Conclusion: In this large registry, we did not observe significant variations among payer classes in management and mortality among women and men after acute myocardial infarction.