Introduction: Regular monitoring and maintaining oral endotracheal tube (ETT) cuff pressure in the normal range in patients undergoing mechanical ventilation in order to maintain adequate ventilation and reduce the risk of complications is essential. This study was aimed to determine the oral ETT cuff pressures in mechanically ventilated patients were admitted to the intensive care unit. Materials and Methods: This cross-sectional study conducted between February 2015 and June 2015. Fifty patients with oral ETT were admitted to the intensive care unit were selected. Pressure of ETT cuff was measured by a standard calibrated manometer. Data were analyzed by SPSS ver 22. Results: The Mean of oral ETT cuff pressure was 53.40 ± 25.42 cm of H₂O. In 76% of cases, the cuff pressure was higher than 30 cm of H₂O. There was no correlation between factors related to patients and ETT cuff pressure. Only significant correlation between the ETT cuff pressure and body temperature was observed. Conclusion: Cuff pressure is often higher than safe limits and regular monitoring of the ETT cuff pressure and preventing its consequences are much recommended.