Background Perioperative outcome data related to metabolic syndrome in coronary artery bypass graft (CABG) patients are lacking. Objective To determine the incidence of metabolic syndrome in CABG patients and whether its presence or the patient’s sex affects postoperative lengths of stay in the intensive care unit and hospital. Methods A retrospective observational study in CABG patients. Risk factors from the Society of Thoracic Surgeons’ Adult Cardiac Surgery Database were used to categorize patients as having metabolic syndrome. Perioperative outcomes were compared between patients with and without metabolic syndrome and between sexes. Outcomes were based on the operational definitions of the Society of Thoracic Surgeons. Results Among 657 patients, 333 had metabolic syndrome; 63.8% (n = 215) of women and 36.9% (n = 118) of men (P ≤ .001). Mean postoperative stays were significantly longer in patients who had metabolic syndrome. Women had longer postoperative stays than did men. Mean postoperative stay for women was 2.7 (SD, 3.4) days in the intensive care unit and 8.2 (SD, 7.1) days in the hospital, compared with 2.0 (SD, 3.8) days in the intensive care unit (P = .01) and 6.6 (SD, 6.8) days in the hospital for men (P = .003). Women with metabolic syndrome also had higher rates of in-hospital death (P = .03). Conclusion Both female patients and patients with metabolic syndrome undergoing CABG surgery are at higher risk for longer postoperative stays. Women with metabolic syndrome are the CABG patients at highest risk for in-hospital death.