In the nineties, the National Institute for Agricultural Research, a public establishment, developed means and structures so as to define and apply a policy for the prevention of occupational risks. After an approach of the prevention policy within the statutory context of health and safety, the memoir then shows how this national policy is applied to one of the twenty one INRA research centres and how it is adapted according to the specificities of this centre. The variety of research and fieldwork activities, which is a characteristic of agricultural research, implies a wide range of work situations and risks that require the action of the prevention specialist. So, he carries out his mission now in laboratories, now in greenhouses, on a dairy farm, a market garden, a fish farm, in an abattoir...