Background: Ventilation with low tidal volume (VT) is advised for critically ill patients to protect against ventilator-induced lung injury and provide better clinical outcomes. Previous studies showed poor compliance with using height to predict the VT. Ulna length has been used successfully to predict protective low VT. Our study aims to evaluate the ability of ulna length measurement to predict accurate protective lung VT in Egyptian people in reference to their standing height. Methods: we included adult healthy volunteers with age ≥ 18 years in this study. The height of each subject was measured while standing upright against a wall. Then, the left ulna was measured with a measuring tape from the olecranon to the mid-point of the styloid process. From ulna length, height was estimated, and protective lung VT was calculated using predicted body weight (PBW). Results: We enrolled 102 participants in this study. The agreement between the calculated VT from standing height and ulna length was analyzed with Bland Altman analysis and showed a bias of (-5.7) ml, and limits of agreements (±1.96 SD) -91 ml to 76 ml. in females, When the calculated VT of ulna length was compared to PBW from height, the predicted mean tidal volume was 6.2 ml/kg (95% confidence interval CI 4.5-7.8 ml/kg). in males, by using ulna length, the predicted mean VT was 6.1 ml/kg (95% CI 4.8-7.4 ml/kg). Conclusion: Ulna length can be used to predict protective lung VT in Egyptian people when compared to their standing height.Trial registration: NCT04644458 ClinicalTrials.gov 09/26/2021