The aim of this study is to identify anatomical structure of petrified wood that was recently discovered in Samarinda, East Borneo. The material consists of a single piece of petrified wood, grey and white in colour. Three dimensional sections (transverse, tangential and radial) were prepared by ground thin-section technique. Microscopic characters of the fossil wood were compared with the present wood species. Specimen was microscopically identified as the petrified wood of hardwood, the existence of wood pores is found as its characteristic. Further, the xylotomical characteristics were closely comparable with the family Dipterocarpaceae. The fossil wood shows a close resemblance with the genus of Shorea in respect to size and arrangement of pores, rays and axial parenchyma. The similarity was found on the anatomical properties of two preparates of Shorea.spp, which are used for comparisons. Therefore, based on specimens properties, the species of this petrified wood is certainly determined as part of the genus of Shorea sp.