INTRODUCTION: Pneumonia is a frequent disease in adults, representing a major health care and economic problems, despite improvement in patient management, community acquired pneumonia remains a leading cause of world wide. OBJECTIVES: The objective of the study is to see the sensitivity, specificity, and accuracy of lung ultrasound in diagnosing pneumonia in the emergency department. MATERIALS AND METHODS: The study was a prospective, study. For the purpose of this proposal, a single centre based study was conducted at emergency department and critical care units of Peerless Hospital &B.K.Roy Research Centre, Kolkata. 124 patients with suspected pneumonia, present to our emergency medicine department, a lung ultrasound was performed on the patient, prior to the chest x rays and chest x–rays were read by radiologist. RESULT: It was found that lung USG Sensitivity: 94.5, Specificity: 97.0, Positive Predictive Value: 98.9, Negative Predictive Value: 86.5 and Accuracy: 95.16 but lung X–ray Sensitivity: 79.1, Specificity: 97.0, Positive Predictive Value: 98.6, Negative Predictive Value: 62.7, Accuracy: 83.8% . CONCLUSION: In conclusion, we believe that lung US in emergency physician hands, for the first approach to patients with pneumonia suspicion, could be an interesting tool for these patients‘ management in our setup