The depth and breadth of science knowledge that is required to educate registered nurses has been the subject of much debate, both nationally and internationally. Central to the debate is the lack of clarity on what science is required for nursing. Nursing students world-wide report anxieties and difficulties with learning science within nursing programmes. It has not been established if science is required for nursing, nor has it been established how science is used by nurses engaged in clinical practice. This research was aimed at examining the use of science in nursing practice and therefore identifying an appropriate undergraduate nursing science curriculum for New Zealand nursing schools. To achieve this aim, a mixed method, interpretive, naturalistic approach has been employed involving interviews, surveys, observation studies and document analysis. The research had four phases; interviews with nine nurse educators and lecturers, written surveys undertaken by 71 registered nurses, observation and in-depth interviews with 17 registered nurses’ in practice across the central and lower North Island, and document analysis. Nurse educators and lecturers were interviewed to gain their perspectives of the role of science in nursing. A Science Attitude and Self-Efficacy (SASE) survey included sections that focused on nurses’ attitudes towards their nursing science courses, attitudes towards science in nursing, and probed their confidence in their own ability to use science in practice. Observations of nurses in their clinical practice were conducted over several hours and the nurses interviewed about their observed actions. The observed nursing actions and espoused science knowledge that were extracted from clinical practice were categorised into science and science-related topics which frame the breadth of content used in nursing practice, and the depth was ascertained by the level of complexity the nurse was able to articulate. Document analysis of curriculum information as well as Nursing Council of New Zealand standards for education, competencies and scopes of practice was also performed to ascertain the importance and relevance of science to nursing practice. Nursing Council documents state that science is important for all levels of nursing practice, from patient observation, to clinical decision-making. Science knowledge assists the nurse when conducting risk analyses and when performing nursing care and assessment. A competent nurse needs to provide advocacy and education for a patient. To be effective at this, a nurse needs to be able to read, critique, understand and translate scientific information and be able to effectively communicate with other health professionals. The majority of nurses in practice felt that science knowledge was the foundation for nursing practice, and that nurses require an in-depth knowledge of science. Nurses who had passed Level 3 secondary school science were more likely to have found studying nursing science courses easy, and had a positive attitude towards using science-in-practice. Those nurses who had a positive attitude towards science were more likely to use in-depth science knowledge in their nursing practice. Nurses who practice in areas where their decision-making is independent and autonomous were more likely to use more in-depth science to inform their practice. Nurses that had a less positive attitude towards science were more likely to have experienced difficulty studying science courses as a student, and were more likely to apply shallow science in their nursing practice. The curriculum design processes within nursing schools may contribute to devaluation of science in nursing. Nursing lecturers were more likely to have a less positive attitude of science’s relevance to nursing practice than nurses in practice. Some aspects of science’s contribution to nursing were unrecognised and may explain why aspects of science-based knowledge and skills that were observed in clinical practice were not represented formally in the reviewed curricula. Nursing science curricula are often represented as discrete packages of science information, whereas in nursing practice, science is entirely integrated. As such, nursing science education needs to become integrated, but explicit within nursing, and its contribution and relevance to nursing more emphasised. Trends in healthcare indicate that the nursing workplace of the future will require nurses to engage in more independent and autonomous practice in the community. This will require nurses who can engage with scientific material, as well be able to innovate and advance nursing practice, which has implications for nursing education. This thesis identifies an appropriate science curriculum for undergraduate nursing in New Zealand and contains recommendations for its implementation.