This paper uses a recursive agricultural sector model to assess the impact of Structural Adjustment Programmes (SAPs) on food security in Benin. The most relevant food security indicators included in the model are food production and its impact on rural income, as well as changes in both food composition at the rural level and the caloric intake of urban consumers. The results show that while the reforms improved nominal income for almost all types of farmers, especially cotton producers and among them particularly those with animal traction, the social costs in terms of urban welfare decline have been high, notably for low and medium-income groups. Simulated food prices are higher with reforms than without, which has led to a decrease in urban consumers'caloric intake (as a percentage of FAO recommended caloric requirements), especially that of low and medium-income households. The results show that poor consumers are very vulnerable: since their intake is very close to the minimum requirements, any external shock in the form of higher food prices endangers their food security. To mitigate the negative effects of SAPs on poor urban consumers, who are the main losers, recommended measures include employment promotion in urban areas, both through public employment or food for work programmes, and promotion of private sector development (résumé des auteurs)