Aim: to evaluate the clinical profile and predictors of outcome of acute encephalitis syndrome patients admitted in PICU. Material and Methods: This Cross-sectional, observational study was done the Department of Paediatrics Anugrah Narayan Magadh Medical College and Hospital, Gaya, Bihar, India for 12 months. All cases were investigated for baseline investigations as well as some specific investigations [Cerebrospinal Fluid (CSF) analysis, dengue serology, radiological investigation] as per clinical presentation. Patient's clinical course, treatment and outcome were noted. Results: out of 100 AES cases most of them were above 10 years of age (33%). Majority of them were males 62(62%), and 38(38%) were females. Most of them belongs to lower socioeconomic status 81(81%), 15(15%) from middle SES; and 15(15%). Out of 100 cases, all had fever; 74 (74%) had altered sensorium ; 70 (70%) had convulsion; 27 (27%) had headache; 41 (41%) had vomiting. On fundus examination 32 (32%) showed papilledema. out of 100 cases 52 (52%) had viral etiology, 25 (25%) had dengue, 6 (6%) had malaria, 4 (4%) bacterial etiology, 6 (6%) had tuberculosis, 6 (6%) had other causes. out of 100 AES patients neuroimaging was done for 36(36%) patients, in which majority had normal finding on neuroimaging, 10(10%) showed Encephalitis features while 6(6%) showed other features like Acute Disseminated Encephalomyelitis (ADEM) in 3(3%), 1(1%) Neurocysticercosis (NCC). Those patients who had shock and need inotropes showed significant mortality (pvalue: 0.012). Also those who required mechanical ventilation had significant mortality, out of 27 patients put on mechanical ventilation 16 died which was statistically significant with p -value 0.001. That patient had deranged Liver Function Test (LFT) profile also had significant higher mortality (p- value: 0.029). GCS on admission, leucocytes counts, serum sodium concentration and duration of hospital stay had no influence on outcome. Out of 100 children of AES admitted in Pediatric Intensive Care Unit (PICU) 71(71%) were discharge, 21(21%) were succumbed, 7(7%) were got Discharge against Medical Advice (DAMA), 1(%) were referred other hospital because of their unaffordability to long duration of ICU stay for ventilator care. Conclusion: AES is an important cause of morbidity and mortality especially during monsoon and post monsoon period. Fever, altered sensorium and convulsion were the important presenting features in AES cases. Viral encephalitis along with dengue encephalitis are important causes of AES. Early stabilization and institution of supportive.