In Nepal, febrile illness is one of the most common reasons for seeking medical attention, but there is limited information on the frequency of specific etiology of fever. This is a retrospective study. Patients presented with fever admitted in medicine ward and Intensive care unit of KIST Medical College, Imadol, Lalitpur from January 2010 to January 2012 are included in the study. Of the 898 patients enrolled, 23.5% had infective exacerbation of COPD. Enteric fever, urinary tract infection, acute gastroenteritis, tuberculosis and community acquired pneumonia were the cause of fever in 20%, 13%, 10%, 7.3% and 6% cases of respectively. Findings confirm the heavy burden of infection was a cause of fever requiring hospitalization. This highlights the importance of simple diagnostic tests and cost effective treatment required to manage these patients.