This paper describes how the categorisation of patients by staff in a French emergency department (ED) leads to the micro-rationing of care. Although ED staff are reluctant to acknowledge it, they refuse to treat many would-be patients at the reception stage, and advise them to go to other care settings (such as general practitioners " premises or social dispensaries). The study analyses the judgmental categories staff use to decide patients' eligibility for care, paying particular attention to their clinical, organisational, moral and social dimensions. Staff ration care at the point of service delivery but they soften the harshness of the rationing by making a positive discrimination in favour of those seen to be in real need. Data from observations and interviews are used to analyse the tensions between the different models of " local justice " employed by doctors.