The clinical course of 363 patients with acute myocardial infarction who did not complete high school education was compared with that of 453 who completed at least high school. Both the in-hospital and 4-year mortality rates were markedly greater for the less educated than for the more educated patients (13 vs 5% [p < 0.001], and 36 vs 17% [p < 0.001]). Adverse baseline characteristics were partially responsible for the increased in-hospital (p = 0.059 after adjustment) and long-term (p = 0.024 after adjustment) mortality. The less educated patients were not as likely to quit smoking after acute myocardial infarction as were the more educated ones (38 vs 49%; p < 0.05). Patients who continued smoking had a greater mortality than did those who quit (24 vs 15% [p < 0.05] for less educated, and 10 vs 4% [p < 0.05] for better educated). Therefore, greater effort should be directed to smoking cessation among the high-risk group of less educated patients. However, the smoking continuation was responsible for only a small portion of the mortality difference, suggesting unidentified causes of mortality, such as lack of compliance with therapy and possible social isolation. Despite the high-risk status of the less educated patients, cardiac catheterization tended not to be performed as frequently as in the more educated patients after discharge from the hospital (16 vs 21%; p < 0.06 at 6 months).