This paper examines the consequences of the transformations of extension services for small scale farms. It presents the results of investigations embedded in regulation theory, which combine a comparative institutional analysis, statistical data processing (national agricultural census) and direct surveys. We describe the transformations in the EU and show that they make it more difficult for small farms to access extension services and to benefit from “front office” support (i.e. direct advice from extensionists). Finally, we emphasize that due to the modification of the knowledge production regime, these small farms may also suffer new specific adverse effects resulting from the re-organization of the "back-office" R&D activities of these extension services (i.e. knowledge base updating, database building, scientific experiments, etc.).