Background The benefit of complete revascularization (CR) during a primary percutaneous coronary intervention (PCI) in patients with multivessel disease (MVD) is still not clear. The aim of the present study was to evaluate the impact of CR in a nonselected population from an all-comers prospective registry of patients with ST-elevation myocardial infarction (STEMI) over a long period of time. Methods and results Between 2004 and 2014, 671 noncardiogenic shock STEMI patients with MVD were included in the present study, of whom 522 were subjected to incomplete revascularization and 149 were subjected to CR. Patients in the CR group were younger [61 (SD 12) vs. 64 (SD 12.4) years old, P = 0.001], more often subjected to femoral access (79.4 vs. 67.1%, P = 0.002), and had a lower number of segments with lesion [2 (2.2) vs. 3 (3.4), P = 0.001]. The CR group tended to have a lower 1-year major adverse cardiac event (MACE) rate (17.8 vs. 25.7%; P = 0.05) that reached statistical significance at 2 years (19.4 vs. 28.5%, P = 0.03). The rates of the individual endpoints were not different between groups. Independent predictors of 2-year MACE were age, femoral access, and previous PCI. Index CR was associated with lower MACE (hazard ratio 0.5, 0.36-0.79). MACE-free survival was higher in the CR group throughout the 2 years of follow-up. Conclusion In patients with STEMI and MVD undergoing culprit lesion PCI, preventive PCI in noninfarct coronary arteries with significant stenosis was associated with a lower risk of MACE compared with incomplete revascularization in this all-comers prospective registry. Copyright (C) 2016 Wolters Kluwer Health, Inc. All rights reserved.