The integration of Antiretroviral Treatment (ART) for HIV in to South African primary health care (PHC) and task shifting are increasing nurses' role in ART and H/V care. There is evidence this role is motivating nurses to adopt more patient-centred care. This study explored this potential emergence of more patient centred care in PHC in the Free State province, South Africa. A multi-site, mixed-method observational approach was used, building on ethnographic principles. A purposive sample of four clinics, two providing ART and two not, were the focus for observation and interviews through four phases of data collection. Emerging findings were explored in an additional six clinics in later phases of data collection. 34 professional nurses, 6 members of clinic staff and 21 patients were interviewed. A thematic analysis that aimed to develop theory grounded in the study contexts through integrating existing theory with inductively identified themes was used. The study found care is patient centred and integrated to a limited extent, while ART and HIV care are more likely to be patient centred than other aspects of PHC. These care routines are then shown to emerge from nurses' agency mediating different levels of structure: the rules of clinic interaction and then the clinic context. Further analysis of nurses' agency explores how it is shaped by a complex identity and a health system context of constant change. The study provides in-depth understanding of a little explored health services issue, and is the basis for recommendations to support patient centred and integrated care. The analysis supports the reconceptualisation of patient centred care to consider Issues of convenience, as a response to the specific context of nurse-led PHC in South Africa. The study also introduces a structure-agency theoretical framework that can be applied to the context of nurse-led PHC.