VALITEST is an EU-funded project built to improve the reliability of diagnostic tests performed in plant health laboratories across the European and Mediterranean region. The project is undertaken by a consortium of 16 partners composed of research institutions, private companies (such as diagnostic kit providers), national plant protection organizations and one intergovernmental organization (EPPO). Current harmonized procedures for the validation and organization of test performance studies will be improved based on the experience gained from the project and by including appropriate statistical approaches, by adapting the process for new promising technologies (e.g. high-throughput sequencing) and by providing new guidelines for the production of reference materials for validation studies. The project will provide a more complete and precise description of the performance of 82 diagnostic tests targeting 11 pests of interest for stakeholders of the region. It will also tackle the need for proficient users by developing a horizontal approach for the evaluation of laboratories’ proficiency and by organizing training activities on the concept of validation. The outcomes of the project will stimulate, optimize and strengthen the interactions between stakeholders in plant health for better diagnostics and lay the foundations for structuring the quality and the commercial offers for plant health diagnostics tools thanks to the creation of a dedicated association and a quality charter.