The reforms which French hospitals have undergone over the last two decades have radically modified their methods of functioning. Hospitals have been asked to modernise in a context of increased constraints and a multiplication of management tools. These changes in the (French) health system bring into question the change capacity of these organisations. We look at the role of organisational routines in the change dynamics of hospitals. Could such routines be a resource for change? Under which conditions? In order to answer these questions we analyse the evolution of absence management organisational routines in two departments of a French hospital – the Emergency Department (ED) and a Nursing Home. Our results show that a balance between the two aspect of a routine, the ostensive, the mental representation of the routine, and the performative, the implementation of the routine, (Feldman, 2000), favours the evolution of the routine and reinforces the change dynamics of the hospital department. Conversely, when the ostensive aspects are weak, the actors are incapable of going beyond the rules and the evolution process of the organisational routine gets blocked. In this situation of imbalance the dynamic of organisational change is itself hampered.