Dengue fever, also known as break bone fever, is a serious mosquito-borne viral infection affecting tropical and subtropical countries. It is caused by dengue virus belonging to family Flaviviridae, having four serotypes that spread by the bite of infected Aedes mosquitoes. It causes a wide spectrum of illness from mild asymptomatic illness to severe fatal dengue haemorrhagic fever/dengue shock syndrome (DHF/DSS) The present study was conducted to diagnose the dengue infection by detecting dengue NS-1 antigen and differential detection of dengue specific IgM and IgG antibodies and to know the seroprevalence of Dengue virus in a tertiary care hospital, R.R.dst. Dengue NS1 and IgM and IgG testing was done by immunochromatography and all positives were confirmed by ELISA. A total number of 164 samples were processed in the laboratory during a period of one year and 36 samples tested positive for dengue infection. Among them 10 were positive for NS1 antigen only, 4 tested positive for both NS1 and IgM, 10 tested positive for IgM, 6 for only IgG and 6 were positive for both IgM and IgG. As dengue related mortality and morbidity is more common, this study was conducted to assess the magnitude of dengue virus infection.