Objectives The objective of this study was to examine the clinical efficacy of clopidogrel treatment on death and recurrent myocardial infarction (MI) among MI patients revascularized by coronary artery bypass graft surgery (CABG). Background The benefit from post-operative clopidogrel in CABG-treated MI patients is largely unknown. Methods All patients admitted with first-time MI between 2002 and 2006, treated with CABG within 180 days after admission, were identified by nationwide administrative registers. Clopidogrel treatment was determined by claimed prescriptions after discharge from surgery. Risk of death or recurrent MI, and of a combined end point of the 2, were assessed by cumulative incidence and Cox proportional hazards model. A propensity score-matched subgroup analysis was done. Results We included 3,545 patients, and of these, 957 (27.0%) were treated with clopidogrel after CABG. Mean follow-up was 466 ± 144 days. Among patients treated with clopidogrel, 39 (4.1%) died or experienced a recurrent MI, whereas that occurred in 203 (7.8%) patients without clopidogrel (log-rank p = 0.0003). Hazard ratio was 0.59 (95% confidence interval [CI]: 0.42 to 0.85) for patients treated with clopidogrel, with no-clopidogrel as reference. By propensity score, of 945 patients with or without clopidogrel treatment who were matched, death or recurrent MI occurred in 38 (4.0%) patients with clopidogrel and 57 (6.0%) without clopidogrel (log-rank p = 0.05). Corresponding hazard ratio was 0.67 (95% CI: 0.44 to 1.00) for clopidogrel users, with no-clopidogrel as reference. Conclusions Among MI patients revascularized by CABG, only 27% received clopidogrel after discharge. Clopidogrel-treated patients had a lower risk of the combined end point of death or recurrent MI. Focus on discharge clopidogrel treatment of these patients should be made.