Health Care Aides (HCAs) provide up to 80% of the direct care to older Canadians living in long-term care facilities, or in their homes. They are an understudied workforce, and calls for health human resources strategies relating to these workers are, we feel, precipitous. First, we need a better understanding of the nature and scope of their work, and of the factors that shape it. Here, we discuss the evolving role of HCAs and the factors that impact how and where they work. The work of HCAs includes role-required behaviors, an increasing array of delegated acts, and extra-role behaviors like emotional support. Role boundaries, particularly instances where some workers over-invest in care beyond expected levels, are identified as one of the biggest concerns among employers of HCAs in the current cost-containment environment. A number of factors significantly impact what these workers do and where they work, including market-level differences, job mobility, and work structure. In Canada, entry into this 'profession' is increasingly constrained to the Home and Community Care sector, while market-level and work structure differences constrain job mobility to transitions of only the most experienced workers, to the long-term care sector. We note that this is in direct opposition to recent policy initiatives designed to encourage aging at home. Work structure influences what these workers do, and how they work; many HCAs work for three or four different agencies in order to sustain themselves and their families. Expectations with regard to HCA preparation have changed over the past decade in Canada, and training is emerging as a high priority health human resource issue. An increasing emphasis on improving quality of care and measuring performance, and on integrated team-based care delivery, has considerable implications for worker training. New models of care delivery foreshadow a need for management and leadership expertise--these workers have not historically been prepared for leadership roles. We conclude with a brief discussion of the next steps necessary to generating evidence necessary to informing a health human resource strategy relating to the provision of care to older Canadians.