In the area around Angkor, a number of ceramic kilns dating from the 9-15th centuries AD have been discovered since 1995. The technical, typological and compositional characterization of their production has been one of the main goals of the Cerangkor Project (Desbat et al. 2008, 2009, 2010, 2011 and 2012). Since 2008, more than 300 samples of Khmer stoneware produced in the Angkor region have been analyzed chemically by XRF-WDS, and forty-three of these have also seen petrographic analysis. The ceramics comprise green-glazed ‘Kulen type’ stoneware and non-glazed stoneware from five kiln sites (Anlong Thom, Sor Sei, Tani, Khnar Po and Bankaong), as well as brown-glazed stoneware from the Anlong Thom site. The data indicate that some workshops used quite similar raw materials for the same types of ceramics, suggesting the exploitation of the same geological formations for the whole region. Differentiation of the compositional groups characterizing each workshop proved, therefore, to be fairly difficult, but small differences allow us to distinguish between some groups of workshops.