Background: One strategy for treating individuals with acute respiratory inflammation (pneumonia) is the prone posture. Prone positioning is a specific treatment that can be used widely in critical care units as a saving therapy. Aim:  to evaluate the effect of prone position on the physiological indices of critically ill patients with pneumonia. Setting: The study was conducted at the intensive care unit of a general hospital affiliated with the Giza governorate. Subjects: A purposive sample of 60 adult patients was selected to achieve the aim of the present study. Design: A quasi-experimental research design was utilized to perform the current study. Tools: Two tools were utilized to collect data pertinent to this study (1) the Patient's demographic and medical data tool & (2) the Patient's physiological indices assessment tool.  The results show that the vital signs and ABG parameters before and after the prone position intervention differed in a highly statistically significant way. Additionally, the ABG parameters and the prone position intervention have a very statistically significant favorable association. Conclusion: In terms of Pao2, Hco3, PH, and Ca +, the current investigation demonstrated a statistically significant positive connection between ABG parameters and prone posture intervention. Therefore, individuals with respiratory conditions like pneumonia may benefit from a prone position in terms of their physiological indices. Recommendations: To generalize the findings, it is advised to replicate the study with a large number of pneumonia patients, and use the prone position when managing patients with pneumonia.