A quality system for a medical laboratory should be directed on all fundamental aspects of its function. This implies the obligation to join the External Quality Assessment schemes, and to make use of its results. It means the setting-up of a quality system according to a medical translation of the items of the EN 45001 standard. And it means taking into account such professional aspects as registration and post-doctoral education, regular contacts with physicians and paying special attention to the suitability of tests. This whole process can be instituted on the basis of an ISO 9000 approach, which means specific standards for the medical laboratories, and inspection, in which the professionals should play an important role. The use of a quality manual facilitates the whole process. It should eventually lead to an accreditation system for medical laboratories. Cooperation in Europe on these aspects is important. An overview is given on the way the system works in the Netherlands.