Abstract: As carers of patients who are clinical research participants, nurses' contribution to the success of clinical trials is acknowledged in the literature. Ethical dilemmas and challenges that clinical trials may present for nurses are also recognised. Although there is some discussion regarding these issues, few studies explore and identify the perceptions of intensive care nurses regarding clinical trials and how they may impact on nursing practice. This thesis explores and describes the viewpoints and experiences of sixty intensive care nurses from a tertiary level referral centre in New Zealand engaged in clinical research activities. The descriptive study utilised a self-administered questionnaire to gather information regarding nurses' roles in clinical trials, associated issues encountered and contributory factors, and the impact of issues on nursing practice, stress and satisfaction levels. Suggestions for potential strategies to minimise the impact of issues on nurses' practice were also sought. Descriptive statistical and content data analyses identified three key areas in which nurses' encounter issues associated with clinical trials and their practice: nurses' workload; ethical concerns; educational preparation and support. The findings indicate that, when issues exist in these areas, routine patient care can be delayed, the enactment of nurses' patient advocacy role can be affected, and nurses' stress and satisfaction levels can be negatively impacted upon. The perceptions of a group of intensive care nurses who are enveloped in the daily balance of patient care, the need for clinical research, and their professional obligations are discussed in this thesis. While the study's findings are reflective of one group of nurses in a distinct practice setting, their experiences can prompt other nurses, research teams and clinical leaders to reflect upon their own clinical research environment.