10.22376/ijpbs.2019.10.1.p1-12 Volume 6 Issue 4 2015 (October - December) Acute Undifferentiated Fever is an emerging problem in India especially during the monsoon months. This study was conducted as a prospective observational study in a tertiary care center to determine the etiology of AUFI. Thirty patients with acute onset fever of less than 10 days duration without any localizing signs were included in the study. Dengue was found to be the commonest cause of AUFI in young adults and also in under fives in monsoon months. Leptospirosis was found to be the next common cause of AUFI. Scrub typhus is also increasingly being reported as a cause of AUFI as we have documented in our study. A large number 36.7% (n=11) of our patients reported dual infections. The predominant group 45.5% (n=5) with dual infections were among those with leptospirosis and scrub typhus and the next common dual infection found was among leptospirosis and dengue. Derangement of liver enzymes along with the positivity of one of rapid tests may be considered as a marker for dual infections suggesting need for further evaluation. P.NEELU SREE AND L.PREMKUMAR Acute Undifferentiated Fever, Serological tests, RT-PCR, Dual infections 715-723