The role that certifications are acquiring in the different chains is one of the most interesting phenomena among those characterizing the agro-food sector. Such increasing use involves two elements strictly intertwined: on one hand, the creation of private, technical norms (standards), establishing the requisites, in terms of hygiene, quality, safety, etc., which producers must comply with; on the other, the carrying out of control activities by private bodies (the certifiers) as to the compliance with the standards. Both the elements offer the chance to analyze an array of new legal problems, with particular regard to: the regulation of the so called certification chain, in relation both to the accreditation of certifiers and to standardization; the liability of the certifiers and of the standardization bodies; the relation between private, technical norms e norms of public origin.