We compared short- and long-term mortality among 334 Mexican Americans and 348 non-Hispanic whites hospitalized for myocardial infarction in the Corpus Christi Heart Project. Age-adjusted 28-day case fatality rates were 37% and 68% greater among Mexican-American women (6.7%) and men (6.2%) than among their non-Hispanic white counterparts (4.9% and 3.7%). Age-adjusted all-cause mortality rates over the next 25-month period, among those who survived the initial 28 days, were similar among Mexican-American and non-Hispanic white women (17.8% and 18.1%), but were 70% higher among Mexican-American men than among non-Hispanic white men (17.4% and 10.2%, respectively). Age-adjusted 25-month coronary mortality rates among initial 28-day survivors were 40% greater among Mexican-American women than among non-Hispanic white women (12.5% vs 9.0%), and 129% greater among Mexican-American men than among non-Hispanic white men (11.4% vs 5.0%, respectively). Thus, nearly all measures of post-myocardial infarction mortality indicated a survival disadvantage for Mexican Americans compared to non-Hispanic whites.