Diamond-cobalt composites are used for cutting tools. Residual stress after manufacture can reduce the lifetime of such composite cutting tools and, hence, the stress state needs to be well understood. Within this study, stress measurements on a cobalt diamond composite were made by SXRD to deduce stress states in the cobalt matrix using the (222) reflection. The application of different apertures allowed the investigation of stress in small areas of cobalt surrounding a diamond and in areas at different distances to a diamond. In the areas adjacent to the diamond increased residual stresses were found in the cobalt matrix. Furthermore, approximations for radial and tangential residual stresses have been derived which show to be different.