ObjectivesThe aim of the study was to investigate the role of ultrasound in the evaluation of movement of the diaphragm and its value in predicting successful extubation in mechanically ventilated chronic obstructive pulmonary disease (COPD) patients in relation to other weaning parameters. Patients and methodsThe present study was conducted on 50 patients in the respiratory ICU and the Chest Department of Ain Shams University Hospitals. Patients were divided into two groups: group A and group B. Group A consisted of 30 mechanically ventilated COPD patients admitted to the respiratory ICU and group B consisted of 20 COPD patients not mechanically ventilated during attendance at the Chest Department. ResultsDiaphragmatic movement was assessed in the two groups. The mean value of diaphragmatic displacement was higher in group B. In group A this value was higher among those with successful weaning using a cutoff value of 1.1 cm with sensitivity of 86.4%, specificity of 87.5%, and accuracy of 89.5%. There was a significant correlation between diaphragmatic displacement and other weaning parameters, which was better in the group with successful weaning. Conclusion Diaphragmatic displacement measuredby ultrasound is one of the most sensitive, specific, and accurate parameters for weaning of COPD patients from mechanical ventilation, especially in relationship with other weaning parameters.