Background: Monitoring the tendency to hypercoagulability during bariatric surgery will be important to predict thromboembolic events. Therefore, we aimed, first, to reveal perioperative coagulation changes obtained from thromboelastogram (TEG) and conventional coagulation assays in certain periods; second, to evaluate their relationships with clinically related factors. Methods: We evaluated 54 morbidly obese patients who underwent elective bariatric surgery. Results: Fibrinogen level was higher than normal in 15 patients. Platelet count decreased, prothrombin time and international normalized ratio increased significantly after surgery while activated partial thromboplastin time remained normal. Hypercoagulability was determined in TEG at three time points at 15, 18, and 11 patients by using maximum amplitude (MA >= 68 mm), and at 5 (%9.2), 11 (%20.3), and 5 (%9.2) patients by using coagulation index (CI > +3), respectively. Age was significantly correlated with postoperative TEG variables: negatively with r and k time, positively with MA, alpha angle, and CI. Females had increased alpha angle and increased MA in TEG when compared with males. One patient has clinically significant fibrinolysis in TEG postoperatively. Conclusion: TEG with increased MA and CI may discriminate patients with tendency to hypercoagulability during bariatric surgical conditions, especially in patients with female gender and increased age.