BACKGROUND Dengue fever is a seasonal and emerging acute mosquito borne arbo-viral illness affecting tropical and subtropical countries. This illness ranges from mild asymptomatic form to severe dengue haemorrhagic fever with or without dengue shock syndrome. In India, the epidemiology of dengue virus infection is very complex and ever changing. Infection has expanded over the last two decades to all regions of the country including hilly states of the northeastern region (Assam, Arunachal Pradesh, Nagaland and Manipur). Aim-To identify dengue seropositive patients by NS1 antigen and anti-dengue IgM antibody detection by ELISA and correlate the changes in epidemiology. MATERIALS AND METHODS A cross-sectional study done from January 2016 to December 2017 with blood samples tested from clinically suspected cases of dengue virus infection.