For many developing countries the decision to offer HIV care and treatment, at what level and through which delivery model was influenced by the associated costs and effectiveness. As South Africa has a high HIV prevalence and a generalised epidemic, there was a need to provide country specific research to guide policy decisions. HE2RO has actively participated in developing and implementing various HIV costing projects. This work has covered a range of cost issues around HIV treatment including the standard cost of ART provision through various delivery models; the cost and outcomes of offering second line treatment; the cost effectiveness of down referring stable patients; and the cost effectiveness of resistance testing prior to changing to second line. This program continues to examine the cost implications of new and proposed treatment guidelines changes as well as providing updated cost estimates for budgeting purposes and inputs into other models.