Japanese encephalitis (JE) is one of the most important encephalitis in globe caused due to arthropod borne (arbo) virus infection. A study was carried out in Dhemaji district of Assam to comprehend the epidemiology of AES/JE cases prevailing in different locality across the district. Out of 48 nos of AES cases reported so far over the year from different areas in Dhemaji district of Assam, 28.13% were found JE positive with a case fatality rate of 44.44%. The predominant age group affected was 0 to 15 years. Clinical symptoms revealed that fever and change in mental state was a common problem among the AES/JE patient. The initial case was noticed during the month of January and since then sporadic cases were reported from different zone under Dhemaji district over the year. However, the incidence of AES/JE cases was elevated during the month of June to July in Dhemaji district of Assam. Most of the AES/JE cases were reported from Sissiborgaon locality followed by Gogamukh whereas the incidence rate of JE cases/deaths was far above the ground in Sissiborgaon and Begenagarah area. Vaccination status confirmed that only diminutive patients were taken JE vaccine. 22.22% of JE positive cases were JE vaccinated and the remaining 77.78% were not vaccinated. One JE positive patient from Sissiborgaon locality expired after taking JE vaccine. This finding should through huge glow to the health authorities to scrutinize the effectiveness of currently used SA-14-14-A vaccine.