Viral-borne diseases have recently gained significant public health importance in the current world. The Viral Research and Diagnostic Laboratory (VRDL) located at Government Theni Medical College (GTMC), Theni, Tamil Nadu, conducts the diagnosis of common virus infections. The purpose of this study is to investigate the seroprevalence of dengue (DENV) and chikungunya (CHIKV) virus infections, as well as their co-infection, in people who have clinical symptoms. From January 2018 to June 2023, serum samples were collected from clinically suspected patients at the tertiary care hospital in Theni, Tamil Nadu. DENV and CHIKV were detected using an enzyme-linked immunosorbent assay (ELISA) in all of the samples. A total of 16,997 cases were enrolled, out of which 11264/2971(26.3%) tested positive for Dengue IgM, 1395/288 (20.6%) for Dengue NS1 Ag, 19/3(15.7%) for IgG, followed by 4319/3388(8.9%) of CHIKV IgM. Fever (n = 16598, 97.6%) was the most prevalent clinical characteristic in all probable dengue and chikungunya patients. Other symptoms were chills (n = 11252, 66.1%), arthralgia (n = 10245, 60.2%), headache (n = 11354, 66.8%), and joint pain (n = 11256, 66.2%). The findings showed a lesser likelihood of acquiring both DENV and CHIKV infections at the same time; however, the risk is still not trivial. This study investigates the clinical presentation of Dengue-Chikungunya patients. The rising prevalence of dengue and chikungunya, as well as their co-infection, need thorough monitoring of endemic areas and good patient care management.