Background/aim: Different techniques exist for the preoxygenation of patients that will be operated on under general anesthesia. Preoxygenation with the deep breath (DB) method may affect cardiovascular stability, which is crucial for coronary artery bypass graft (CABG) patients. In this study, we aimed to compare the effects of the 3 min TVB preoxygenation technique and 1 min 8DBs technique on hemodynamic response and arterial oxygenation in patients with normal ejection fraction that were scheduled for elective CABG surgery. Materials and methods: Forty patients classified as ASA II?III and scheduled for elective CABG surgery were randomly assigned to TVB/3 min or 8DBs/1 min for preoxygenation. Cardiovascular variables, i.e. heart rate, mean arterial pressure, central venous pressure, cardiac index, systemic vascular resistance index, and stroke volume index, and arterial blood gas samples were analyzed before and after preoxygenation and at the end of the apneic period before intubation. Results: The preoxygenation methods affected the hemodynamic response similarly. PaO2 increased significantly with 8DBs compared to the TVB at the end of preoxygenation but was similar between the groups at the end of the apneic period (respectively, P: 0.03; P: 0.15). PaCO2 changes were similar between the groups. Conclusion: In patients with normal ejection fraction scheduled for CABG, 8DBs can be an alternative to TVB preoxygenation. Our results should be compared with those of other studies.