The application of cleavages on SiC epitaxial layers are presented as a feedback for an evaluation of the growth. The preferred cleavage planes are described and discussed in relation to the atomic configuration of the SiC lattice. From the cleavages it is possible to relate defect behaviour to the growth mechanism and obtain information which can not be revealed by studying as-grown epilayer surfaces. For demonstration, a variety of defects revealed by cleavages are investigated for SIC epitaxial layers.