A comprehensive quantitative petrographic database of sandstones used by the Khmers for sculptural purposes would be a helpful tool for archaeologists, museum curators and others interested in pursuing research on early stone usage, geological source and provenance. Towards that end, this paper presents quantitative petrographic analysis of stone materials used in the production of some free-standing sculptures and architectural elements in the Koh Ker style of the 10th century from the collections of the National Museum of Cambodia and The Metropolitan Museum of Art. These materials are compared to samples from the quarry of Thmâ Anlong near the foothills of the Phnom Kulen, Sieam Reap province. Primary and secondary detrital modes and key grain-size parameters are used to identify three sandstone types. The free-standing sculptures are carved from feldspathic arenite and feldspato-lithic to litho-feldspathic arenite. Finely carved lintels are worked from a quartz arenite, which is significantly richer in quartz grains and of a finer grain size. The geological source of the two other lithotypes will have to await detailed geological survey of the Koh Ker area accompanied by petrographic study of selected samples from documented quarries. The significance and potentiality of quantitative petrographic study of Khmer stone materials are shown in supporting and integrating archaeological investigations in South-East Asia.