This paper reports on a systematic review that sought to answer the research question: What is the impact of the primary and community care nurse on patient health outcomes compared with usual doctor-led care in primary care settings? A range of pertinent text-words with medical subject headings were combined and electronic databases were searched. Because of the volume of published articles, the search was restricted to studies with high-level evidence. Overall, 31 relevant studies were identified and included in the review. We found modest international evidence that nurses in primary care settings can provide effective care and achieve positive health outcomes for patients similar to that provided by doctors. Nurses are effective in care management and achieve good patient compliance. Nurses are also effective in a more diverse range of roles including chronic disease management, illness prevention and health promotion. Nevertheless, there is insufficient evidence about primary care nurses' roles and impact on patient health outcomes.