In line with its strong position in clinical research, Belgium was one of the first European Member States where the implementing regulation of the Clinical Trials Directive is fully operational. The specific conditions provided for in the legislation concerning experiments on the human person reinforce Belgium as a very attractive host for clinical trials, ensuring a lasting environment for innovative research. This new edition of the Operational Guidance does not only analyse the Belgian law from the perspective of the sponsor of a clinical trial, but also addresses the roles and tasks of all parties involved in clinical trials.