Background: Respiratory issues such as atelectasis and bronchopneumonia are more common in patients in the intensive care unit (ICU). Objective: The aim of the present study was to investigate the impact of chest mobilization exercises on vital signs and respiratory parameters in mechanically ventilated children. Subject and methods: Fifty children who had pneumonia and received mechanical ventilation were enrolled in this study. Their mean ages were 3.8 ± 2 and 4.06 ± 1.9 years in the control and study groups respectively, and they required mechanical support. The children were divided randomly into two equal groups: conventional chest physical therapy group and combined chest mobilization with conventional chest physical therapy group. Heart rate, respiratory rate, tidal volume, minute ventilation and fraction of inspired oxygen were recorded before and after the study. Results: There was a significant increase in tidal volume in favor of the combination group (p < 0.05) with no significant change in respiratory rate, heart rate, minute ventilation and fraction of inspired oxygen between both groups (p>0.05). Conclusions: Combined chest mobilization exercises with conventional techniques of physical therapy were found to have a substantial impact on respiratory parameters in mechanically ventilated children and improve air entry into the lungs.