This paper presents a new reference object, so called “CT ball plate”, used for metrological performance testing of industrial CT systems, and discusses both the calibration procedure using a tactile coordinate measuring machine and the first results carried out using an industrial CT scanner. This artefact can be used to determine several characteristics of the CT system like, probing errors of spheres, length measuring errors between sphere centers, measurement errors in the whole CT volume and effects in connection with image artefacts.