Background: Rickettsial diseases are re-emerging in India. Acute undifferentiated febrile illness is a difficult case to treat (AUFI). The greatest problem for clinicians is the early diagnosis of these diseases when antibiotic therapy is most successful.To determine the prevalence of RDs, therapy outcomes, and socio-demographic factors associated with RDs in AUFI. Patients and Methods: Fever and/or clinical signs of Rickettsial infection in patients admitted to the CIMS teaching hospital in Chamarajanagar for four years. Purposive sampling found AUFI in 1638 people. The diagnosis of rickettsial disease relied on clinical features. The Weil-Felix test was one. Then came a 48–72-hour estimate of doxycycline response. Results:Out of 1810 AUFI cases, 198 (10.93%) were rickettsial, with 190 (95.95%) having an RGA score of 14 or more, and 18 (9.09%) having an RGA score of 14 or less. Males aged 30-40 were most affected. Leucopenia, thrombocytopenia, etc. were found. Doxycycline was effective in 151 (89.35%) of cases within one week of onset. The remaining 18 (10.65%) required longer-term doxycycline with other drugs, three had severe complications, and one died. RD prevalence 70.01 %. Enteric fever, Dengue fever, Chikungunya fever, and Rickettsial diseases were the most common diseases diagnosed in patients with undifferentiated febrile illness.