Objective: Early invasive strategy, defined as early coronary angiography and subsequent revascularization, when appropriate, is recommended by current guidelines for the management of patients with moderate- to high-risk acute coronary syndromes. We sought to compare the outcomes of patients with acute coronary syndromes undergoing surgical revascularization with an on-pump versus off-pump approach. Methods: Among a total of 13,819 patients with moderate- to high-risk acute coronary syndromes enrolled in the Acute Catheterization and Urgent Intervention Triage Strategy trial, 1375 patients were triaged to isolated coronary artery bypass grafting. One thousand one hundred fifty-four patients underwent operations with cardiopulmonary bypass (the coronary artery bypass grafting group), and 221 patients underwent off-pump coronary artery bypass grafting (the off-pump coronary artery bypass grafting group). Propensity score matching (1:3) was applied to adjust for differences in baseline clinical and angiographic characteristics, yielding a total of 880 matched patients with acute coronary syndromes (220 managed with off-pump coronary artery bypass grafting and 660 managed with coronary artery bypass grafting). Results: At 30 days, patients undergoing off-pump coronary artery bypass grafting had fewer events of bleeding (43.7% vs 56.3%, P = .0005) and myocardial infarction (7.3% vs 12.1%, P = .055) but higher rates of reintervention (3.7% vs 1.2%, P = .02). At 1 year, there was no difference between groups in death, total myocardial infarctions, reinterventions, strokes, or major adverse cardiac events, but there was a lower rate of non-Q-wave myocardial infarctions in the off-pump coronary artery bypass grafting group (4.6% vs 9.2%, P = .03). Conclusions: In this large-scale study evaluating the outcomes of patients with acute coronary syndromes, off-pump coronary artery bypass grafting was associated with lower rates of bleeding and non-Q-wave myocardial infarction but more reinterventions early after the procedure. At 1 year, there was no major outcome difference between the 2 surgical strategies.