Aim: The aim of the study is to determine systematically the performance of existing clinical prediction score (SMART_COP, CURB_65, PSI, ATS/ IDSA, SCAP Score) to risk stratify the Emergency department patients with Community acquired pneumonia. Method: This study was conducted on 80 patients presented to the department of emergency medicine, during July 2016 to November 2019. Results: Maximum age group of 51-70 with mean age 57.5 ± 14.78 years. Smoking about 75% males have smoking as risk factor and the most common comorbid condition is hypertension. Among 80 patients, 10 have CURB_65 score of 0, 24 patients have score of 1, 30 patients have score of 2, 11 patients have score of 3, 3 patients have score of 4 and 2 patients have score of 5. Among 80 patients, 19 patients has SCAP major criteria and 36 patients had minor criteria. The mortality was seen in about 10 patients. SMART_COP has highest AUC value among different pneumonia severity score for predicting the need of vasopressor support and SMART_COP score > 5 have good accuracy in predicting the need of vasopressor support in patients with CAP. Conclusion: Early microbiological diagnosis, early antibiotic administration in patients with SMART_COP score > 4 and PSI class 4 and 5 can decrease the morbidity and mortality in CAP patients.