Lowland tropical forest in the Lower Dibang Valley district in the state of Arunachal Pradesh is the prime habitat in India of the eastern hoolock gibbon (Hoolock leuconedys). The present study was conducted to assess the threats to the population of H. leuconedys in the unprotected forest fragments of the Lower Dibang Valley district, Arunachal Pradesh. Besides field observations, we employed a structured questionnaire survey method to interview villagers, including the Gaon Burha (village head) and local hunters. Based on our observations and the interviewees' responses, we recorded that gibbons were occasionally hunted for bushmeat, and that dogs, the Mountain Hawk Eagle (Nisaetus nipalensis), and monitor lizards (Varanus) were evidently predators of, particularly young, gibbons in the fragmented forest patches. Indirect threats included habitat destruction and fragmentation, deforestation, extraction of non-timber forest products, livestock grazing, road construction, selective (illegal) logging, shifting cultivation, commercial cash-crops, and permanent human settlement. A conservation action plan is urgently needed to protect and conserve the eastern hoolock gibbon from extinction in the region.