Purpose: To compare the prognosis of patients with a first Q-wave versus non-Q-wave myocardial infarction (MI) in the reperfusion era. Methods: Patients with a first MI were compared according to type of infarct-Q-wave (n = 1,786) versus non-Q-wave (n = 722)-and by treatment with thrombolysis. Results: Patients with non-Q-wave MI were more likely to be female and to have undergone previous coronary revascularization. Their 30-day mortality rate was 7%, as compared with a rate of 9% among patients with Q-wave infarction (adjusted odds ratio [OR] = 0.6, 95% confidence interval [CI]: 0.4 to 0.9). However, the subsequent 30-day to 1-year mortality rates were similar in patients with Q-wave or non-Q-wave MI. Patients who were not treated with thrombolysis and who had a non-Q-wave MI had a lower 30-day mortality rate (OR = 0.6, 95% CI: 0.3 to 0.9) but a similar 30-day to 1-year mortality rate (hazard ratio [HR] = 1.5, 95% CI: 0.9 to 2.5) as compared with their counterparts who developed Q-wave infarction. Among thrombolysis-treated patients, 30-day (OR = 0.8, 95% CI: 0.4 to 1.5) as well as 30-day to 1-year (HR = 1.2, 95% CI: 0.5 to 3.0) mortality rates were similar between patients who developed either Q-wave or non-Q-wave MI. Conclusions: Patients who received thrombolysis had similar early and late mortality rates after the index infarction regardless of whether they had a Q-wave or non-Q-wave MI. Conversely, among patients who were not treated with thrombolysis, patients with a non-Q-wave MI had lower early mortality rates but similar long-term mortality rates as those with Q-wave MI. Copyright (C) 2000 Excerpta Medica Inc.