The study was conducted at Forest College and Research Institute, Mettupalayam, during 2019 to 2022, to determine the specific gravity of Pterygota alata at different girth classes. The samples were collected from seed origin of Pterygota alata which were farm grown in Pollachi, India with a specification of four different girth classes (30-45, 45-90, 120-150,150-180cm) and three radial and axial positions. From each sample tree, three stem discs with a 2 cm thickness were cut in both the axial (25, 50 and 75 % height of the tree) and radial (pith, middle and periphery) position then the samples were converted to the 2×2×2 cm3 cubes. The highest specific gravity at radial position was observed in 150-180 cm girth class with a value of 0.67, 0.58 and 0.44 g/cm3 in green, air dry and oven dried wood samples and the lowest specific gravity was recorded in 30-45 cm as 0.629, 0.629 and 0.432 g/cm3 respectively. Whereas in axial position the highest specific gravity was observed in 150-180 cm girth class with a value of 0.69, 0.59 and 0.44 in green, air dry and oven dried wood samples and the lowest specific gravity was recorded in 30-45 cm as 0.62, 0.50 and 0.44 respectively. The study suggested that the Pterygota alata specific gravity is more of less similar to the low-density hardwood species and it will be the alternate prominent species for ply wood, packing cases, match splints and pencil industries.