This report presents the results of a survey of over 800 genetic testing laboratory directors in 18 OECD countries. It provides the first detailed overview of the availability and extent of molecular genetic testing across OECD member countries. The survey asked questions about what sorts or laboratory policies and practices are in place to to assure the quality of human genetic testing and the proficiency of those that carry out such tests. It includes information on policies regarding samples and genetic data handling, as well as the transborder flow of specimens. The survey allowed the OECD to compare practices in individual countries in order to inform international action in setting standards and developing guidelines for practice. Based on the survey results, the report puts forward recommendations for action for better quality assurance and proficiency of molecular genetic testing. It shows, for example, that requirements for licensing and accreditation/certification of diagnostic molecular genetic testing laboratories have not penetrated OECD countries to a high degree or with any consistency. Considerable variations exist in mechanisms of licensing, certification and accreditation, including the standards by which tests are performed, results are reported, and the qualifications for laboratory personnel. This survey was carried out between June and October 2003 in Austria, Belgium, Canada, the Czech Republic, Finland, France, Germany, Ireland, Italy, Japan, Norway, Portugal, Spain, Sweden, Switzerland, Turkey, the United Kingdom and the United States. Over the following three years, based on the results of this survey, the OECD Working Party on Biotechnology developed Guidelines for Quality Assurance in Molecular Genetic Testing which were approved as an OECD Council Recommendation in May 2007. (See www.oecd.org/sti/biotechnology/qualityassurance for a free download of the Guidelines.)