Dusky leaf monkey (Trachypithecus obscurus obscurus), are widely distributed in Peninsular Malaysia. The shortage of studies on phylogeographic structure of T. obscurus, at subspecies and population level, as well as the absence of study for the population in Gunung Ledang National Park, Johor, Malaysia, it may adversely affect their conservation management. This study aims to determine the phylogenetic position of T. obscurus at subspecies and population level, as well as the absence of study for the population in Gunung Ledang National Park, Johor, Malaysia, it may adversely affect their conservation management. This study aims to determine the phylogenetic position of T. obscurus in Gunung Ledang and compare it to those of other Malaysian populations using the D-loop region of mitochondrial DNA. Faecal samples were collected from the wild population in Gunung Ledang and sequenced, and used in phylogenetic analysis with six additional genetic samples of T.obscurus from other regions in Peninsular Malaysia, and one sequence of Presbytis melalophos from GenBank. Both neighbor-joining and maximum parsimony trees indicate that populations from Gunung Ledang should beclassified as T. o. obscurues and are monophyletic with thea populations from Endau-Rompin, Johor, and Selangor. This study provides a new insight and contributes to the conservation management strategies of T. obscurus in Malaysia. [ABSTRACT FROM AUTHOR]