BACKGROUND:This study was undertaken to evaluate the role of Ultrasound sonography in diagnosing suspected Community Acquired Pneumonia(CAP) and comparing its efficacy with standard Chest X ray(CXR) in Emergency Department. Early identification of CAP is of great clinical importance especially for countries like India for better targeting of limited resources.MATERIALS AND METHODS: This study is based on prospective analysis of 100 patients aged 50.07 +/- 15.68 from November 2017 To April 2018 who were presented with suspected Community Acquired Pneumonia. Pregnant,Pediatric patients were excluded from the study.Lung Ultrasound Sonography(LUS) was performed under supervision of intensivist. Chest x ray (CXR)done for all cases and radiologist was blinded for LUS report . The final diagnosis was established by CXR or CT scan.RESULTS: We studied diagnostic accuracy of LUS in 100 suspected cases of CAP with inclusion and exclusion criterias. we had 90(90.0%) positive lung ultrasound (LUS) and 70(70.0%)CXR positive cases. In 20 (20.0%) cases LUS was positive with negative CXR. CAP could not be confirmed with lung ultrasound in 10(10.0%) patients. Computed tomography (CT scan) was performed only in patients with negative CXR. i.e. 30(30.0%) cases. Lung ultrasound and chest X-ray were compared as diagnostic tools, a significant difference was observed between them (p <0.05).Specificity can be inferred from this study because the real gold standard is CT, which could not be performed in all patients.CONCLUSION: These data show that LUS is a potential additional imaging technique to CXR and chest computed tomography (CT), with the advantages of a shorter time of execution and interpretation, and lack of ionizing radiation. This study confirms that LUS is a simple,reliable ,rapid ,safe imaging tool, to facilitate diagnosis of lung lesion ,it is not inferior to CXR in identifying pleuropulmonary abnormalities in patients with suspected community acquired pneumonia, hence ER physician ,Pulmonologist, Intensivist,General physician should be aware of potential contribution of LUS in diagnosis of CAP.It can replace CXR to diagnose CAP in Emergency Department.