Background After myocardial infarction, African Americans have been reported to undergo fewer catheterization and revascularization procedures than whites, but few studies have addressed racial variations in the delivery of thrombolytic therapy. Methods We conducted a retrospective analysis of data prospectively collected on consecutive patients admitted with acute myocardial infarction to the 16-bed coronary care unit of a large, urban teaching hospital. Results Over a 5-year period, 1948 consecutive patients were admitted with acute myocardial infarction to a single coronary care unit. Thrombolysis was administered to 19% of 1024 African Americans and 29% of 924 whites (P <.01). The initial diagnostic impression on admission was “definite” infarction less often in African Americans (30%) than in whites (43%, P <.001), a difference that appeared to largely account for the difference in thrombolytic administration in a multivariable model. Mortality adjusted for age and concomitant illnesses was similar in African Americans compared with whites (relative risk 1.0, 95% confidence interval 0.78 to 1.51). Conclusions Much of the racial variation in thrombolytic administration could be accounted for by differences in clinical presentation, an issue that requires further study. (Am Heart J 1999;137:338-45.)