This study analyses residual stress measurement using X-Ray diffraction method on ultrafine-polycrystalline diamonds and polycrystalline diamonds films grown using Hot Filament Chemical Vapour Deposition technique (HFCVD) on silicon nitride(Si3N4) and tungsten carbide (WC) substrates in the same chamber at the same time with varied pretreatments prior to HFCVD diamond deposition. Measurements were taken perpendicular to the surface and the measured residual stress states of the diamond films are in compression. Thus, assuming isotropic properties of the film, the diamond films grown have tension residual stress parallel to the surface of the substrate. Residual stress is estimated to have the lowest stress for substrate that has undergone 5g/liter silicon carbide seeding process. Effects of residual stress to adhesion are discussed for both substrates.