Objectives;Scrub typhus is an important cause of acute febrile illness and need to be differentiated from other causes of febrile illness such as malaria, enteric fever, dengue etc. The present study reports a recent epidemic of scrub typhus amongst cases of PUO from different areas of Rajasthan, India. There was high mortality in undiagnosed cases of PUO which lead to the diagnosis of scrub typhus.  Methods; Patients presenting with undiagnosed febrile illness between January 2013 to December 2015 were evaluated. Testing was done using a commercial ELISA kit for specific IgM antibodies against Orientia tsutsugamushi. Results; 793samples (23.81%) were  positive for the presence of  IGM antibodies against O tsutsugamushi. The number of adult male and female positive patients were 19.09%( 368/1927) and 28.58% (425/1487) respectively. Serum samples of FUO cases were analysed for IgM antibodies to Orientia tsutsugamushi along with dengue, malaria, typhoid. The cases were seen mainly in the months between August to November. Conclusion: The present study emphasises the importance of scrub typhus among cases of PUO especially after rainy season and during early cooler months. The study also highlights the significance of ELISA method for rapid and early reporting and ruling out scrub typhus in PUO cases.