OBJECTIVE To investigate the prevalence of preoperative hypercoagulability assessed by thromboelastography (TEG), to identify patient characteristics associated with hypercoagulability and to explore whether hypercoagulability is associated with a greater risk for myocardial infarction (MI), stroke and mortality 30 days after coronary artery bypass grafting (CABG) surgery. METHODS This is a prospective, observational study of 200 consecutive CABG surgery patients. Hypercoagulability was defined as TEG maximum amplitude >69 mm. RESULTS Eighty-seven out of 200 (43.5%) CABG patients were TEG-hypercoagulable. In univariate regression analysis, age, female gender, hypertension, severe chronic obstructive pulmonary disease, platelet count and fibrinogen level were significantly associated with TEG-hypercoagulability. Multivariate regression analysis revealed higher age, platelet count and fibrinogen levels as variables independently associated with TEG-hypercoagulability. Thirty-day outcome data: MI (TEG-hypercoagulable 6.9% vs. TEG-normocoagulable 3.7%, NS), stroke (8.0 vs. 2.8%, NS) and mortality (4.6 vs. 0.9%, NS). There was a significant difference in 30-day combined event rate of MI, stroke and mortality (17.2 vs. 6.6%, P = 0.019). In univariate analysis, only female gender and TEG-hypercoagulability were significantly associated with 30-day combined event rate. In multivariate analysis, only female gender was significantly associated with 30-day outcome (P = 0.014), whereas TEG-hypercoagulability demonstrated a trend (P = 0.065). CONCLUSIONS Hypercoagulability identified by TEG was preoperatively found in 43.5% of CABG patients, and the findings of this study support the notion that TEG-hypercoagulable patients have a higher risk for a combination of thromboembolic complications and death after surgery.