Although research on the production of CVD grown diamond layers, and its material properties, has been ongoing for many years, unsolved problems remain. A particular problem concerns the adhesion of the layer to the substrate and subsequent delamination. The primary factor influencing adhesion is the presence of internal stresses, resulting mainly from the difference in the thermal expansion coefficients of substrate and layer material. In this work the influence of layer thickness and microstructure on the internal stress in otherwise identical CVD-grown diamond coatings is investigated using X-ray diffraction technique, i.e. conventional sin(2)-psi methods is applied. Furthermore, the independence of both microstructure and crystallographic texture with the stress state will be addressed.