Abstract: In India, the Hoolock gibbon, Hoolock hoolock, is found only in a small part in the northeast, south of the Brahmaputra River and east of the Dibang River. The Hoolock gibbon, a canopy dependent species, occurs in some reserve forests of Cachar district of Barak Valley, Assam. but its numbers is declining due to habitat loss and hunting. They are now surviving in some isolated pockets in the reserved forest areas, where they are occur in scattered groups and fighting for survival. A status survey was done in the Inner line reserved forest and its adjoining areas from July 2010 to Dec. 2011. Ten family groups and thirty-three individuals made up the total count. Of these the adult males and females comprised of 54.54% while the sub-adults, juveniles, and infants were 27.27%, 12.12% and 6.06% respectively. In activity budget, maximum time (%) spent in feeding i.e. 23.30% followed by foraging (27.90%), resting (23.50%), calling (3.10%) and others (13.20%). Adequate protection of existing protected areas, ban on timber logging, control of jhum cultivation and poaching, and conservation education/awareness and mass involvement of the local communities can help this valuable species to survive in their natural habitats in Barak Valley, Assam. The present paper deals with the population status and activity budgeting of Hoolock Gibbon in the Inner line Reserve forest and its adjoining areas of Cachar district of Barak Valley, Assam.