These last years, a number growing of publications show the interest and the need to use evidence-based practices and directives in the assistance brought to the drug addicts. Those present an analogy with the term ''evidence-based medicine'' referring to the application of interventions and medical prescription considered to be effective and empirically founded.Within the framework of the ''Research programme in support of the federal drugs policy document'', a study was carried out by the Antwerp University (UA), Ghent University (UGent) and Social Defense Research Center (CRDS). This article reports the difficulties and the recommendations, resulting from this research, for an implementation of the evidence-based practices in the drug addiction treatment.