Drawing on a socio-historical analysis of the work of agricultural advisers, this article explores the conduct of modernisation policy following the Second World War. The advisers played a crucial role in this, by recommending new methods of production and encouraging farmers to mobilise as a group. They relied on technical know-how as well as their practical knowledge of the agricultural milieu. Above all, they showed huge ingenuity in demonstrating their devotion to their farmer clients, without evading the framework set by their employers. These capacities for adaptation so essential to their profession were initially highly valued. Then, from the 1970s onwards, they attracted criticism for their failure to conform to the new imperatives of bureaucratisation, specialisation and commercialisation in agricultural advice.