Lorises are very unique creatures that live on trees. As a result of habitat destruction, they have become a rarity and are on the verge of extinction. Sam Popham’s Arboretum, Dambulla is Sri Lanka’s only dry zone Arboretum where an amazing spectrum of trees, birds, butterflies, dragonflies, and mammals can be observed in their natural setting. The slow Lorises are now identified as a heavily threaten group of animals and declared as threatened species in Sri Lanka. Therefore, it is an urgent necessity to take measures to protect them in their habitats. There are no studies reported so far on different habitats and the distribution pattern of the Loris population at Sam Popham’s Arboretum. The main objective of this research is to study the distribution pattern and population estimation of Grey Slender Loris in different habitats at Sam Popham's Arboretum. The number of Lorises, its gender, maturity (adult/juvenile) and the species of tree (with the height) which Lorises were spotted were recorded and tagged. The data was collected for a period of seven months from January 2019 to July 2019. The results obtained so far showed that Lorises are restricted to certain specific tree species. Although the forest is rich with large no trees belonging to several families, they commonly occupied species such as Pamburu (Pamburus missionis), Daduwa (E. bracteata), Welan (P. suberifolium), Elapath Habarala (Diospyros ferrea), and Ahatu (Ficus tinctoria). Furthermore, the Lorises were sighted at a height of 5 feet and above. According to the results, 31 Grey Slender Lorises were found and 14 of them were adult males, six were adult females and 11 were juveniles. Out of the tree species, Daduwa (E. bracteats) has the highest number of loris sightings consisting of 4 adult Lorises all were male adults. Elapath Habarala (D. ferrea), Ahatu (Ficus tinctoria) and Velan (P. suberifolium) each consist 3 Grey Slender Lorises which were 3 adults males, 1 female and 4 juveniles. As per the present study, during the full moon, the Loris sighting was relatively low compared to other days due to the moonlight. However, during the study, an average of 3 Lorises can be observed within a period of 2 hours. This indicates that there is a good population of Lorises within the Arboretum. Therefore, the establishment of similar Arboretums and enhancing the knowledge of the general public will help to uplift the rapidly declining Loris populations in the area.Keywords: Loris, Arboretum, Dambulla, Distributio