Revision of the key European performance standards on wood preservatives and treated wood (EN 335, EN 351 and EN 599) is due to be completed by the end of 2003, and preparation of standards for remedial treatment products is under way. This paper briefly describes progress and reviews the work being done to support development of these standards. Past practice in the UK was to specify a process; the approach in the European Standards is "results-based". Difficulties in verifying that the required penetration and retention of preservatives are achieved in practice are discussed. 4 pages.