Dengue fever is considered to be one of the major health problems in south east Asia. In the recent past, epidemic outbreaks of Dengue have also been noticed in India. Initially, the neurological manifestations which were associated with Dengue received little attention, but now, there have been several reports of encephalitis and encephalopathy . However, nowhere in the literature has Dengue fever been mentioned as a cause of acute psychosis or mania. Here, we are reporting a 21-year-old male, a resident of Delhi, India who after the Dengue infection, developed an episode of classical mania.