There is increasing pressure for development agencies to play a role in developing an ‘AIDS-competent’ society – one where everyone is able to assess and make decisions about factors related to the causes and consequences of HIV/AIDS and to generate the means and mobilise the resources to respond to HIV/AIDS. Mainstreaming HIV/AIDS into the core business of development has been seen as an important part of the process of achieving this vision of society. But the question of what mainstreaming means in practice and how a community-led NGO should go about it, is still being debated. The role of the community becomes critical at every level, from on-the-ground services through to national-level policies. The process of moving towards AIDS competence needs to evolve through a spiral of learning, action and reflection, challenging problems and making the best use of available opportunities. By promoting the role of the community, HIV/AIDS becomes fully mainstreamed into sustainable and relevant development plans. ACORD Tanzania’s experiences suggest that mainstreaming HIV/AIDS goes hand in hand with a rights- based approach, as it allows the agency to identify and tackle some of the underlying causes of HIV/AIDS vulnerability which are rooted in social inequality and social exclusion. The active involvement of people living on the margins of society can be facilitated by addressing lack of knowledge and/or denial of individual rights to information, power, goods and services. In the context of HIV/AIDS, this approach entails tackling the deep-seated gender inequalities that greatly increase the vulnerability of women and young girls (as well as men and boys), whilst at the same time challenging the stigma and discrimination of PLHA.