Nowadays coordinate measuring machines (CMM) are featured by a great degree of complexity and high accuracy of manufacturing. During use of a machine, usually after periodical maintenance it is highly recommended to perform a verification test according to the same procedures as a standard verification test, including a difference, that performance conformity is checked with user’s declaration. Periodical verification should be performed as often as it comes from a user’s experience and after every interference influencing on mechanical and electronic systems of a CMM, that potentially could cause a change in its accuracy parameters. The best solution is employing for that purpose an independent accredited laboratory, that is featured by high competence and experience. In the paper rules of acceptance and periodical verifications are described, sources of measurement errors resulting from CMM imperfections are presented as well as examples of results for specific measurement devices installed in industry were shown.