Background: The development of professional values in nursing is directly related to quality and ethical clinical practise and may also increase practitioner and patients' satisfaction. Some factors, such as work setting or work experience, can influence the importance granted to the professional values of nursing. Objectives: To compare in primary care nurses and hospital care nurses the importance granted to professional values and to contrast this perception as a function of professional experience. Research design, participants and research context: Descriptive cross-sectional study. Participants were 380 nursing professionals from the public health system (primary care and hospital care). Three dimensions were analysed: ethics, professional expertise and professional mastery. Data were collected from January to June 2015. Ethical considerations: We obtained permission from the Ethics Committee and participants' informed consent. Findings: Hospital care professionals attached more importance to all the values analysed, regardless of their work experience. Ethical values, such as confidentiality and respect for the person, were considered to be very important in both systems. Values related to professional expertise obtained lower scores, especially in primary care. In general, professionals with more than 20 years' experience granted less importance to the values. Conclusion: The professional setting influenced the importance assigned to professional nursing values, and clear differences were observed between primary and hospital care. The domain of ethics was considered the most important. It is necessary to reflect on the significance attributed to professional values, especially in more expert nursing staff. [ABSTRACT FROM AUTHOR]