BACKGROUND Great modifications in social and family relationships and life style come from rapid urbanisation in developing countries. Various types of malnutrition coexist in these towns. Food consumption outside the home is more and more common. This in turn encourages rapid growth in the food informal economic sector which must be taken into account in food and nutrition policy and planning. The aim of this study was to analyse the characteristics and complementarities between home and outside the home food consumption of different kinds of individuals coming from different kinds of families in Bamako, in terms of expenditures and aspects of food and nutritional intakes. METHODS 366 individuals from 74 families were interviewed. They were chosen according to defined criteria in three districts of Bamako of high, middle and poor socio-economic level. RESULTS At home the daily food expenditure is 2.27 and 3.79 times greater per individual in rich than in middle income and poor families respectively. Animal proteins are respectively 41%, 19% and 9% of daily protein intake. Energy from lipids is 20 to 30% in rich and middle families. In poor ones it is only 15% which is the lower limit of nutritional recommendations. Moreover, contrary to proteins and carbohydrates, the cost of lipids seems, almost incompressible. Almost everybody eats out of home food, particularly children. Its cost, on an energy basis, is higher than home food. The expense is 19 to 27% of the family food budget. It appears necessary to the satisfaction of nutritional requirements in middle income and poor families. Despite various costs, whatever be the socio-economic level, energy intakes coming from that food are equivalent in absolute terms among various kinds of individuals: children, men and women. CONCLUSIONS Families had to adapt their food strategies after the 1994 Franc CFA devaluation. Various hypotheses are presented, linked to intra-family relationships and, within poor families, to insertion in the street food economic sector, in order to understand, the logic of food choices. Such an analysis, where health, nutritional, economic, social and cultural aspects of food are taken into account, allows some concrete orientations for urban food and nutrition policy.