In today’s world  the   high prevalence of local individual diseases makes the prioritization of the differential diagnoses of a clinical syndrome of acute undifferentiated febrile illness (AUFI) necessary. So the present study was planned to detect the spectrum of etiology of AUFI prevalent at our tertiary care centre.   The clinical data and serological test reports of the AUFI cases treated at our hospital in the past 6 years (2011–2016) were included in the study. The commonest cause of AUFI was Typhoid fever (16%). This was followed by Dengue (8%). The Leptospirosis (14%), Scrub typhus (21%) are emerging infections on the rise, which needs to be on the clinicians’ mind while diagnosing AUFI at our tertiary care centre. The prevalence of Chikungunya viral fever (3%) is on the decline . On analysis of the available data for three years  an increase in both the number of patients tested for Scrub typhus and number of positive samples were found. Leptospirosis also showed a similar trend like Scrub typhus. This signifies that more of testing is necessary to rule out Scrub typhus and Leptospirosis among AUFI cases. One factor which needs highlight is the incidence of dengue cases is still observed throughout the year in contrast to the incidence of Chikungunya cases which is on the decline. This study highlights the need for further research to look for the factors aiding the survival of Dengue, and also the role of vaccination in the eradication of Dengue.