Over 150 countries with around 500 million people suffer mosquito borne diseases every year resulting in approximately one million deaths. Around 40 million people in India contract mosquito borne diseases annually. Mosquitoes are responsible for causing illnesses such as malaria, filarial, dengue, chikungunya, yellow fever etc. If not detected in time, these diseases can turn out to be deadly. Dengue virus causes dengue. Incubation of the disease is 3-14 days. The disease is characterized by headache, high fever, joint pains, and skin rashes and vomiting. Recovery period may be upto 7 days. A severe form of the disease, dengue haemorrhagic fever shows symptoms such as bleeding from capillaries under the skin and vomiting. Dengue virus is a single stranded RNA arbovirus and resembles chikungunya and zika virus. It is an arthropod borne disease caused by four serotypes of the virus. During recent years an increase in the number of cases of dengue has been noticed. The present study was carried out in the central laboratory of Govt. Medical College, Bharatpur, and Rajasthan. The purpose of the study was to determine seropositivity, seasonal variation and clinical profile of the disease during the period January to December, 2019. Serum was separated from the blood samples of 997 patients with Dengue like illness. The samples were tested for Dengue NS 1 antigen and IgM antibody ELISA. On testing by ELISA it was found that 102 out of 647 (15.7%)samples were positive for NS 1 antigen and out of 350, 78 (22.2%) were tested positive for IgM antibody (Table 1). It was found that total prevalence of dengue in Bharatpur was 18%. It was also seen that out of the total number of 997 fever cases, maximum were in the age group 1-30 years. Rainy season (August to November) showed the maximum number of cases with the peak in October.