The implementation in 1999 of the ISO 9001:2000 in LATU, where 21 chemical, physical and biological laboratories had got UKAS and DKD accreditation, based first on ISO Guide 25 and later on ISO 17025, for more than 100 tests and calibrations in 1998, determined a change in the quality system management which included the definition and planning of the testing and calibration process and had a positive impact in the compliance of ISO 17025 requirements that range from improvement in the customers satisfaction indicators up to the assurance of the appropriate test and calibration’s uncertainties. Based on a process approach, control and improvement of the testing and calibration process were performed by an “improvement team” lead by the process responsible and composed by representatives of each laboratory, the administrative and commercial areas and the maintenance and human resources sections as representatives of the critical interactive processes. The establishment of specific objectives for the testing and calibration process which included analytical quality and management objectives developed from the policy, derived in several actions of the “improvement team” which in the last four years determined: improvement of laboratory’s response (time elapsed in reporting tests and calibrations diminished 70%)