Dengue virus infection has emerged as a notable public health problem in recent decades in terms of the mortality and morbidity associated with it. Dengue is endemic in many parts of India and epidemics are frequently reported from various parts of India and abroad. The case fatality rate in patients with dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) can be as high as 44%. Hence based on above findings the present study was planned for Study of Seroprevalence of Dengue Infection in Clinically Suspected Cases of Dengue at NMCH, Patna. The present study was planned in Department of Microbiology, Nalanda Medical College and Hospital Patna, Bihar, India. The study was conducted from August 2019 to December 2019. In the present study 909 patients of suspected dengue cases were evaluated. A single blood sample approximately 2-3 ml was collected from each patient in a plain vaccutainer tube with all aseptic precautions. Serum was subjected toNS1, IgG and IgM antibodies by enzyme linked immunosorbent assay (ELISA) Kit provided by NIV Pune. The data generated from the present study concludes that Dengue cases were more during September to December in the post monsoon season which is useful to plan special preventive strategies. The study draws attention toward the male, young adult age group. Discrimination of primary and secondary dengue infection is important as the possibility of DHF and DSS are more in secondary infection.