The ‘Violence against Kosovar Albanians NATO’s intervention 1998-1999’ case study describes the constraints and dilemmas facing Médecins Sans Frontières teams that witnessed a process of terror and expulsion which they described as the ‘deportation’ of Kosovar Albanians by Serb forces. It also described MSF’s reaction to NATO aerial bombings and the control exercised over the refugee camps by this party to the conflict. Should MSF denounce the violence being committed against Kosovars at the risk of being excluded from access to these people and of encouraging the NATO intervention? Should MSF take a stance on the NATO intervention? What sort of relationship should be established with countries that were committed either militarily (such as NATO members) or politically (Greece) in the conflict and their civil societies? Should MSF raise the alarm about the absence of the UNHCR in the management of the refugee camps, at the risk of reinforcing this marginalization? Is it justifiable to carry out an assessment mission that sacrifices the principle of operational independence, by invoking an interpretation of the principle of impartiality that implies a responsibility to assist victims on both sides of a conflict?