The effect of health-related quality of life on in-hospital outcomes after coronary artery bypass grafting surgery has not been investigated in international multicenter studies. We hypothesized that poor preoperative health status is associated with mortality and length of hospital stay.In the Multicenter Study of Perioperative Ischemia Epidemiology II, preoperative Short-Form 12, Mental Component Summary (MCS), and Physical Component Summary (PCS) scores were obtained prospectively from 4,811 patients (3,834 men, 977 women) undergoing coronary artery bypass grafting surgery at 72 centers in 17 countries. Primary outcome measures were in-hospital mortality and prolonged (>14 days) length of hospital stay.One hundred fifty-one patients (3.1%) died. After adjustment for regional differences, a 10-point reduction in MCS score was associated with higher mortality risk (odds ratio [OR] 1.17, 95% CI 1.004-1.37, P = .04) and prolonged hospital stay (OR 1.11, 95% CI 1.01-1.21, P = .03). The preoperative PCS score was not associated with mortality risk but significantly predicted prolonged length of hospital stay (OR 1.20, 95% CI 1.09-1.33, P <.001). There was no significant interaction between gender and either the MCS or the PCS score.The preoperative PCS predicted prolonged postoperative hospital stay, whereas the preoperative MCS score was an independent predictor of both prolonged length of hospital stay and mortality. Preoperative assessment of health-related quality of life factors with the Short-Form 12 might be a useful tool for risk stratification and planning for hospital discharge and rehabilitation.