A variety of nurse practitioner education and training programmes are currently offered. They are designed to prepare experienced nurses to undertake an expanded role and a broader range of activities. Since the introduction of this new nursing role many nurse practitioners are now working in primary care health care teams. This study aimed to investigate how the working patterns of primary care teams have been altered as a result of the introduction of the nurse practitioner into the primary care team, the ways in which nurse practitioners' skills are integrated into the primary care team and other team members' perceptions of this new nursing role. The study was exploratory and a qualitative methodology was chosen. Phase one consisted of three focus groups with three primary care teams including nurse practitioners. Phase two involved audiotaped, semi-structured interviews with nurse practitioners (n = 4) and general practitioners who worked with nurse practitioners (n = 3). The data were subsequently transcribed, reduced and analysed using a theoretical framework appropriate to the research design. Nurse practitioners operated in a variety of ways in primary care. Key clinical activities included triage, physical examination, diagnosis and decisions about the treatment and care of individuals and specific groups of patients. The conditions dealt with by nurse practitioners were generally less complex than those seen by GPs but an element of overlap occurred. The nurse practitioners emphasized the importance of offering patients a choice about whom they prefer to be seen by. Most team members were supportive of the new team member, although some were confused about the role and others were opposed to the introduction of a new specialist nurse post. The findings indicate a need for role clarity, definition and official recognition.