['Early and long-term outcomes of coronary artery bypass grafting (CABG) in patients with left main disease (LMD) with acute coronary syndrome (ACS) have never been assessed.', 'Between September 2004 and April 2012, 459 patients with LMD underwent first-time isolated CABG. Of those, 191 patients had ACS and 268 did not. Early and late postoperative outcomes were compared between two groups.', 'Patients in the LMD+ACS group were older and more likely to be female. Left ventricular ejection fraction was lower in the LMD+ACS group. In both groups, bilateral internal thoracic artery grafts were used in over 90% of patients and off-pump technique in over 95%. Operative death rate was not significantly different between the groups (LMD+ACS: 2.1% vs.', '0.4%). Log-rank test revealed that the actuarial survival rate (79.2 ± 3.7% vs. 81.5 ± 3.5%) and freedom from major adverse cardiac and cerebrovascular events (MACCE) (69.2 ± 4.2% vs. 67.0 ± 4.1%) were similar between groups at 7 years. Multivariate analyses demonstrated that ACS was not identified as an independent predictor of operative death, late mortality, and late MACCE.'] Does acute Coronary Syndrome Have a Negative Impact on Outcomes after Coronary Artery Bypass Grafting in Patients with Left Main Disease?