The Indian Giant Squirrel Ratufa indica, an endemic species to India, is widely distributed from the evergreen to moist and dry deciduous forests of Western and Eastern Ghats and the central Indian hills. Although several studies were conducted on the ecology of this species all over India, little is known on the density and distribution of this species from this region. In the present study an attempt has been made to study the population density and distribution of the Indian Giant Squirrel at Sivilliputhur Grizzled giant squirrel Wildlife Sanctuary which is a part of the Periyar-Agasthyamalai landscape of Southern Western Ghats, Tamil Nadu, southern India, during 2011-12. The study results revealed that the present mean population density of Indian giant squirrel 6.9 ± 2.9 individuals / Sq Km in Srivilliputtur Wildlife Sanctuary and this density estimates from this area will provide baseline data for future study. Present study is also addressed the issue of urgent need of survey the status, distribution and abundance of Indian giant squirrel in Srivilliputtur Wildlife Sanctuary.