In charge with the development of quality assurance in a university hospital, the authors have recorded actions realised in medical departments to improve quality. A first questionnaire was sent to every physician (340) and every chief nurse (170). The 126 answers allowed to pick 467 actions out and to identify 72 professionals who were involved in quality actions. These last ones have been asked during semi-directive interviews in view to describe those actions, their results and difficulties encountered. The main actions consisted in writing procedures (197), animating working groups (84) or department reunions (54), realising studies (54) or measuring indicators (33). This study shows the professionals' dynamism who spontaneously develop actions to improve the quality of care. It also shows the limits of these actions because of a lack of specific resources and methods.