BackgroundSolo medical practices in primary healthcare delivery have been abandoned in favor of interdisciplinary teamwork in most Western countries. Dynamics in interdisciplinary teams might however be particularly difficult when two or more autonomous health professionals develop similar roles at the practice level. This is the case of family physicians (FPs) and nurse practitioners (NPs), due to the fact that the latter might accomplish not only the traditional role proper to a nurse, but also several medical activities such as requesting diagnostic exams and prescribing medical treatments. The tensions that this overlap might generate and their implications in regard of the development of professional identities, and consequently of the quality of health care delivered, have been suggested, but rarely examined empirically. The goal of this study is to examine identity work, i.e., the processes of (re)construction of professional identities, of NPs and FPs working together in primary care interdisciplinary teams.MethodsA longitudinal, interpretive, and comparative multiple (n = 2) case study is proposed. Identity work theory in organizations is adopted as theoretical perspective. Cases are urban primary care multidisciplinary teams from two different Canadian provinces: Quebec and Ontario. Participants are NPs, FPs, managers, and patients. Data gathering involves audio-diaries, individual semi-structured and focus group interviews, observations, and archival material. Narrative and metaphor techniques are adopted for analyzing data collected. Within- and cross-case analysis will be performed.DiscussionFor practice, the results of this investigation will: (a) be instrumental for clinicians, primary care managers, and policy decision-makers responsible for the implementation of interdisciplinary teamwork in primary healthcare delivery to improve decision-making processes and primary care team performance over time; (b) inform continuing interdisciplinary professional development educational initiatives that support competency in health professionals’ identity construction in interdisciplinary primary care organizations. For research, the project will contribute to enriching theory about identity construction dynamics in health professions, both in the fields of health services and primary care education research.