Within current neo-liberal approaches to development, models of community-driven development assume that community-based workers (CBWs) are key actors in improved and accessible service delivery. We argue that use of CBWs is under-theorised and seems to be based largely on untested assumptions about community participation and responsibility. Drawing on case studies on potable-water management and home-based care for HIV/AIDS patients in Tanzania and South Africa, the article explores issues of accountability, professionalism, and personal motivations in systems involving CBWs. It argues that many assumptions in relation to the effectiveness of CBW programmes require re-visiting.