The purpose of this document is two-fold. It serves as a practical training manual for World Bank staff, Ministry of Education planners and other stakeholders who wish to implement the Ed-SIDA model in a particular country to assist with educational planning in the face of HIV/AIDS. It also serves as an introduction to the epidemiology of HIV/AIDS, the impact it can have on the education sector, its scale and how this can be captured empirically by the Ed-SIDA model. The threat of HIV/AIDS on education is so extensive in certain settings that no planning initiative should be without specific strategies aimed at estimating and mitigating the impact of this disease. The Ed-SIDA model represents a powerful spreadsheet based tool for educational planners to effectively create these strategies and quantify the impact of HIV/AIDS on the educational sector. In this way, anecdotal evidence of teacher mortality, absenteeism and class sizes is substituted with estimates derived in an informed and systematic manner. Ed-SIDA can be seen to consist of two components. The first focuses on the impact that HIV/AIDS has on the supply of education. For each country, supply refers to estimates of the number of teachers, their HIV prevalence and deaths due to AIDS to be projected into the future (next 10 yrs) under different recruitment policies. These projections are made both in the presence and absence of an AIDS epidemic, allowing the impact of HIV/AIDS to be clearly described. Using this model World Bank staff and Ministry of Education planners can look at the implications of HIV/AIDS for recruitment policies and how they may be changed in response. The second component of the model focuses on the impact of HIV/AIDS on the size and characteristics of the school-age population in a given country - the demand for education. Most important with respect to demand is the number of school-aged children who have been orphaned by AIDS. The challenge to enroll them and other vulnerable children will have to be met. The relationship between supply and demand are explained in terms of pupil to teacher ratios, which are key to estimating required teacher numbers for national EFA goals in presence of HIV/AIDS. Additionally, the financial costs of HIV/AIDS related to teacher training, absenteeism and enrolment of orphans is illustrated in examples for countries currently in the high prevalence setting of an established epidemic, such as in eastern and southern Africa, and in a low prevalence (but rising) setting of an emerging epidemic, such as in west Africa. The Ed-SIDA model is implemented in an Excel©-based spreadsheet format called edsida.xls. This spreadsheet is fully annotated and may be modified by the user to produce impact analyses relevant to their country of interest.