This chapter analyses the debates and tensions that characterise the field of organic agriculture. 1 These tensions concern the principles, but perhaps more often, the practices and systems put in place to implement organic agriculture, which can lead to an important gap between the discourse and the facts about organic food. We analyse the specifications and the mechanisms of certification and accreditation in organic food and explore the three poles of the ‘tripartite standards regime’ that define organic food. To reflect on these tensions two models are compared: the ‘official’ AB label supported by public policies, and private standards such as Nature & Progrès. Although these private standards are less significant when measured by volume and turnover, they are promoted by very active actors in different social and political forums. The case of organic agriculture e enlightens the relations between market and political rationalities and the synergies and contradictions that they generate.