This chapter, Legal Background and Procedures on Pesticides, provides an overview of the main topics and legal procedures for the regulatory toxicology of pesticides in the European Union. Legal requirements and procedural steps for approval of active substances, as well as the authorisation of plant protection products and biocidal products, are described, particularly those relevant to regulatory toxicology and human health risk assessment. Furthermore, an overview is given of the procedure of setting of maximum residue levels for plant protection products as a prerequisite for the authorisation of plant production products and the stipulation of import tolerances. Based on the different regulations, comprehensive information is given on the data requirements, evaluation, risk assessment and decision making regarding human health assessment. Further information is provided on the mutual recognition of products and simplified authorisation procedures for special product types.