Background Chest physiotherapy has been used to clear secretions in pediatrics for many respiratory problems. The aim of this study was to investigate the effect of chest physical therapy on full term neonates with primary pneumonia. Materials and Methods Sixty full term neonates admitted to neonatal intensive care unit (NICU), Minia University, Egypt, during the period from September 2016 to September, 2017 divided into two equal groups: group I included 30 patients received routine medical treatment according to American Academy of Pediatrics (AAP) recommendations and group II included another 30 patients received routine medical treatment plus chest physical therapy modalities in the form of positioning, postural drainage, percussion and vibration. We compared between the two groups as regards the duration for mechanical ventilation and/or oxygen therapy, clinical improvement, oral feeding and duration of hospitalization. Results There was significant differences between group I, neonates who received routine medical treatment) and group II, neonates who received routine medical treatment plus chest physical therapy regarding the duration needed for mechanical ventilation and/or oxygen (p<0.045), the duration needed for clinical improvement (p<0.042), the duration needed for oral feeding (p<0. 035) and the duration of hospitalization (p<0. 031). Conclusion According the results, chest physical therapy has a positive supportive effect on full term neonates with primary pneumonia regarding the duration needed for mechanical ventilation and/or oxygen therapy, the duration needed for clinical improvement and the duration of hospitalization.