Carbon sequestration in degraded agricultural soils in developing countries to mitigate atmospheric greenhouse gas concentrations is increasingly promoted as a potential win–win strategy, particularly for drylands. While considerable effort has been made to assess the benefits for local soils, regional ecosystems, as well as the global climate, few estimates exist regarding detailed costs and benefits for local smallholders, the ultimate actors and beneficiaries of carbon offset projects. This paper presents a farmer-centered ex-ante cost–benefit analysis of 15 management and land use options combined with a household budget model to assess what practices are most profitable and economically feasible for local farmers in the Old Peanut Basin of Senegal. The results show significant differences in anticipated net benefits for various management options, ranging from −$1400 to $9600 tC −1. Given the differential resource-endowment of local smallholders, carefully designed cost-sharing mechanisms would be necessary to achieve equitable and efficient local participation in carbon sequestration schemes.