Non-governmental community-based organizations have been identified as central to effective HIV/AIDS related prevention and care. This paper reports on the activities and achievement of one such organization--Grupo Pela VIDDA, Brazil. It details the philosophy and commitments which have underpinned the group's action in three related fields--care and support, prevention and advocacy. The paper traces the origins of these commitments to ideals articulated by the new social movements whose impact is beginning to be felt, albeit unevenly, in Brazilian society today. It analyses the impact of Pela VIDDA's work to date on individuals, organizations and communities at risk.