This guideline describes procedures for testing the performance of large coordinate measuring machines of various designs and makes. It applies to: acceptance tests serving to verify compliance of the CMM and its probe with the manufacturer?s specifications, reverification tests performed by the user for periodical checking of the CMM and its probes, interim checks performed by the user for monitoring the CMM and its probes in-between reverification tests. The guideline considers both manual and CNC-controlled coordinate measuring machines of single- as well as multi-arm designs.