Background: This study was originally prepared for the African Inter-Ministerial Conference on Literacy (September 2007) with the objective of analysing the costs of successful adult literacy programmes run both by government ministries, as well as international and national non-governmental organisations. Objectives: This study aims to increase the evidence base available on costs by examining adult literacy programme costs in the context of operational details and budgeting processes. It was intended to add to the limited amount of data currently available, and to provide broad recommendations regarding the calculation of costs. Methodology: In addition to estimates relating to costing currently available in the published literature, details of nine successful adult literacy programmes were obtained through a combination of web-searches, documentation received from organisers in response to an open-ended e-mail questionnaire and telephone calls. These are described, together with a presentation of their cost structure and our calculation of their unit costs. Particular attention was paid to "hidden" costs in terms of central or provincial government costs, to contributions by NGOs and other partners and to in-kind contributions in examining the new empirical data. Findings: Information from this study suggests that a realistic estimate of the costs of making an adult literate would be a minimum of US$100, the maximum estimate currently stated in LIFE documents. Despite an up to fivefold variation in unit costs with little obvious reason for this, the large diversity in modalities, objectives and target audience of the programmes explains much of the wide range in unit costs remarked upon by other authors. Conclusions: We believe that it would be premature for any country to pre-define the appropriate costing structures, and what is an allowable range of unit costs, based on this information. Recommendations are made for what factors should be taken into account when calculating unit costs. Each country should consider making an inventory of the large scale programmes that exist or are being developed as a preliminary step to deciding whether or not it is appropriate to impose a costing framework or proposing a specific range of unit costs. However, there is a demonstrable need for more general agreement about the components that should be considered in any costing of an adult literacy programme. Significance: This study contributes to the evidence base for developing a framework for analysing and allocating the costs of non-formal adult education projects in a manner to facilitate future planning. (Contains 8 tables.)