Given that one of the goals of public health policy in Quebec and Canada is to reduce social inequalities in health and welfare, it is surprising, to say the least, that most information systems in this field make no mention of people's socio-economic characteristics. The present article proposes an index to reflect the material and social dimensions of deprivation as this concept has been developed by Peter Townsend and other authors. The article describes the method used to create the index, which uses census data and tools developed by Statistics Canada to match postal codes with enumeration areas. Examples are provided of the use of the index in information systems covering three aspects of health and welfare in Quebec: deaths, hospitalizations and births. The value of the information provided by this index in planning health and social services is demonstrated.