To evaluate clinical implication of prediabetes, we compared a 2-year major clinical outcome including patient-oriented composite outcomes (POCOs), stent thrombosis (ST), and stroke between prediabetes and diabetes in patients with ST-segment elevation myocardial infarction (STEMI) and multivessel disease (MVD). A total of 4097 patients with STEMI and MVD (normoglycemia [group A: 1001], prediabetes [group B: 1518], and diabetes [group C: 1578]) who received drug-eluting stents were evaluated. Patient-oriented composite outcomes were defined as all-cause death, recurrent myocardial infarction (MI), or any repeat revascularization. The cumulative incidences of POCOs, ST, and stroke were similar between groups B and C. The cumulative incidences of all-cause death (adjusted hazard ratio [aHR]: 1.483; 95% CI: 1.027-2.143; P = .036) and all-cause death or MI (aHR: 1.429, 95% CI: 1.034-1.974; P = .031) were higher in group B than in group A. The cumulative incidences of all-cause death (aHR: 1.563; 95% CI: 1.089-2.243; P = .015), cardiac death (aHR: 1.661; 95% CI: 1.123-2.457; P = .011), and all-cause death or MI were higher in group C than in group A. In conclusion, prediabetes could potentially have a similar impact as diabetes on major clinical outcomes in patients with STEMI and MVD.