This paper describes the possibilities of using the Ballbar QC20-W diagnostic tool for long-term monitoring of geometrical accuracy of CNC machine tools. By introducing regular checks, the production capability and the planned machine maintenance should be increased. The publication presents the results obtained from a case study. The case study describes the procedures and results of introducing a regular inspection into the manufacturing process at the MCV 754QUICK (KOVOSVIT-MAS) three-axis machining center are presented to use statistical tools for long-term machine condition monitoring.