In this work we investigate the effect of processing at high pressure-high temperature (HPHT) on the adhesion of CVD diamond coatings on WC-Co substrates. The samples consisted of WC-Co substrates coated with thin diamond films (10 – 40 μm thick) grown by microwave plasma (MWCVD) CVD. The substrates were previously etched in order to remove the Co from the surface region. The adhesion of the film and its wear resistance improved after the HPHT treatment. SEM images of the cross section of the coated substrate revealed that Co infiltrated back to the region where it was previously removed. The results indicate that it is possible to take advantage of the HPHT plants already available around the world to produce, besides PCD's and diamond powder, high-performance CVD diamond cutting tools with the advantage of requiring less demanding processing conditions.