Abstract Background: Pneumonia is one of the leading causes of neonatal morbidity and death in many developing countries. It is Characterized by inflammation of lungs, pneumonia leads to an accumulation of respiratory secretions in the airways, which contribute to worsen clinical symptoms and increase airway resistance, making it difficult for children to breathe. Aim of Study: To investigate the efficacy of prolonged slow expiration technique on oxygen saturation and blood pressure among neonates with pneumonia. Subjects, Material and Methods: This randomized con-trolled trial included 32 neonates with pneumonia. Their gestational age is from (33-36) weeks and chronological age from birth till 28 days. The participants were randomly allocated into 2 equal groups. The control group received conventional chest physiotherapy, while the study group received conventional chest physiotherapy in addition to Prolonged Slow Expiration Technique (PSET) for 20 minutes duration per session, two sessions (each session was two hours after feeding to avoid vomiting) per day. First session in the morning and the second session in the afternoon, from admis-sion in neonatal intensive care unit (NICU) till discharge. Oxygen saturation (SaO2) and blood pressure (BP) were measured and chest X-ray was done. All measurements were recorded at baseline and at discharge in this study. Study Design: Prospective, randomized controlled trial. Results: Significant increase in O2 saturation of control and study groups post treatment compared with pretreatment (p<0.01). There was no significant difference in blood pressure and number of sessions between groups post treatment (p>0.05). Conclusion: A prolonged slow expiration techniquein-creases O2 saturation of study group compared with that of control group post treatment. So prolonged slow expiration technique is an excellent supplement to conventional chest physiotherapy in managing pneumonia in neonates.