Background: Shifting from mechanical ventilation to spontaneous breathing during weaning phase is a very critical challenge and its success depends on many factors including the adopted weaning strategy in each center. Few studies compared the used weaning procedures in pediatric age groups and their impact on the vital signs as stress predictors during spontaneous breathing trial. Aim of this work To compare between t-piece weaning tool and pressure support ventilation during spontaneous breathing trial in mechanically ventilated pediatric patients in order to assess patient’s suffering. Methods: This prospective cohort study was carried out in pediatric, chest and anesthesia ICUs, Zagazig University Hospitals; Egypt, over 6 months period. One hundred and four ventilated patients aged from 2 months to 18 years were enrolled in this study. All patients were subjected to full clinical assessment with comparative method between pressure support ventilation (PSV) and T-tube (TT) ventilation during weaning process. Results: It was found that cardiac arrhythmias accounted for 71.2% of patients weaned on TT in the form of sinus tachycardia, compared to 9.6% of patients on PSV with significant difference between the two groups(p<0.001). Also, there was a significance increase in the mean arterial blood pressure among patients on TT during weaning process with increase in the work of breathing (p<0.001). PSV mode had significantly lower PCO2 than T-tube during weaning (P<0.001). The failure rate was higher when using T-tube during spontaneous breathing trial (SBT) in comparison to PSV with more exposure to another weaning trials. Conclusion: We concluded that PSV has less stressful impact on patients during SBT process. T- tube weaning procedure has higher failure rate than PSV.