Since 1994, integrating human immunodeficiency virus/sexually transmitted disease (HIV/STD) services with primary health care, as part of reproductive health, has been advocated to address two major public health problems: to control the spread of HIV; and to improve women's reproductive health. However, integration is unlikely to succeed because primary health care and the political context within which this approach is taking place are unsuited to the task. In this paper, a historical comparison is made between the health systems of Ghana, Kenya and Zambia and that of South Africa, to examine progress on integration of HIV/STD services since 1994. Our findings indicate that primary health care in Ghana, Kenya and Zambia has been used mainly by women and children and that integration has meant adding new activities to these services. For the vertical programmes which support these services, integration implies enhanced collaboration rather than merged responsibility. This compromise between comprehensive rhetoric and selective reality has resulted in little change to existing structures and processes; problems with integration have been exacerbated by the activities of external donors. By comparison, in South Africa integration has been achieved through political commitment to primary health care rather than expanding vertical programmes (top-down management systems). The rhetoric of integration has been widely used in reproductive health despite lack of evidence for its feasibility, as a result of the convergence of four agendas: improving family planning quality; the need to improve women's health; the rapid spread of HIV; and conceptual shifts in primary health care. International reproductive health actors, however, have taken little account of political, financial and managerial constraints to implementation in low-income countries.