The standard ILO classification for pneumoconiotic changes using conventional X-ray films has become well established. In recent years computed tomography has played an increasing role in occupational medicine and above all in the assessment of pneumoconiosis. Therefore a standardised method of classification for CT also seems necessary. A system of classification developed by occupational hygienists and radiologists allows a detailed description of parenchymal and pleural changes and the use of 28 additional symbols. Furthermore, special diagnoses relevant to occupational medicine and additional comments can be made. The classification system was tested in practice in the research project "Early diagnosis of asbestos-related diseases" (Frühdiagnostik asbestverursachter Erkrankungen). It was shown to be both practicable and easily reproducible, intra-individually and interindividually.