Background: Although endotracheal suction (ETS) is a crucial practice, it is not free of complications and hazards particularly when operated improperly or/and critical condition. Therefore, it is particularly important to perform this procedure with professional competence, especially among high risky groups with threatening conditions. Aim: This study aimed to assess cardiothoracic care nurses' practice and beliefs toward endotracheal suction post coronary artery bypass graft at teaching hospital. Materials and Method: A cross-sectional descriptive study conducted at cardiothoracic care unit (CTCU) at the teaching hospital. A convenience sample of thirty-two nurses utilized self-administrated scale to assess nurses' beliefs and observational checklist to assess their level of practice toward Endotracheal Suction Post Coronary Artery Bypass Graft at Teaching Hospital. Results: Mostly of the studied nurses were female and had technical institutions. Most of them (56%) had a moderate level of practice and adequate beliefs toward suction post coronary artery bypass graft. However, there was a statistically significant correlation between their level of practice and beliefs. Conclusions: Approximately all the studied nurses had a moderate level of practice in terms of ET suctioning with adequate level of beliefs, and mostly of them did not attend training courses toward endotracheal suction post coronary artery bypass graft at teaching hospital. Recommendations: An in-service trainer must conduct continuous training courses to improve nurses' practice and enhance their beliefs toward Et suction. Cardiothoracic care nurses should be updated with nursing guidelines and oriented toward the use of advanced suction equipment and technique to promote the provided practice and their beliefs.