The complex division of labour in health care has encouraged the analysis of occupational boundary disputes between separate professions. Less attention has been directed at the divisions in individual occupational groups but in a context of intensive health sector workforce reform there has been a growth in lower status occupations. This article extends debate about lower status occupations by exploring the manner in which nurses and healthcare assistants engage in boundary work to advance their occupational interests. The UK government's modernization agenda has encouraged a more prominent role for healthcare assistants and the findings confirm that this agenda has reinforced occupational boundary disputes between nurses and healthcare assistants. Tensions between nurses and healthcare assistants took particular forms influenced by gendered notions of caring work. The consequences of these boundary management strategies in terms of work undertaken, pay and status are also explored.