Background: Carotid intima-media thickness (CIMT) is associated with an increased risk of cardiovascular disease. We studied whether CIMTpredicts the prognosis of Asian patients with acute ST-elevation myocardial infarction (STEMI). Methods: A total of 345 patients with STEMI (men, 82.9%; age, 59 ± 13 years) treated with emergent revascularization were prospectively investigated. In all patients, common CIMT was measured with high-resolution ultrasonography. The patients were followed for a median period of 583 days, and the primary end point was major adverse cardiovascular events (MACE) defined as a composite of cardiovascular death, heart failure, nonfatal recurrent MI, revascularization, and stroke. Results: Mean CIMT of the patients with STEMI was 0.77 ± 0.14 mm. Of the total patients, 20.6% had carotid plaque and 11.0% experienced MACE. Killip class, left ventricular (LV) function, and carotid plaque were associated with 30-day MACE, whereas CIMT and carotid plaque were related to overall MACE. After adjusting for age, the event rate was 19.0% in the third-tertile CIMT (≥ 0.83 mm) group, 12.1% in the second-tertile (0.70-0.82 mm) group, and 4.3% in the first-tertile (≤ 0.69 mm) group (. P= 0.01). Carotid plaque was independently associated with a higher incidence of MACE (adjusted odds ratio [OR], 3.7; 95% confidence interval [CI], 1.327-10.234; P= 0.012). Area under the receiver operating characteristic (ROC) curve for CIMT tertile (0.69 ± 0.05) was significantly larger compared with those for door-to-balloon time (0.55 ± 0.05), LV ejection fraction (LVEF) (0.49 ± 0.05), and Killip class (0.48 ± 0.05) (. P < 0.001). Conclusions: CIMT was a useful prognosticator to predict future cardiovascular events (CVEs) in Asian patients with STEMI.