Study objective: To identify ethical issues encountered by staff in the development and implementation of public health activities at two sites in Scotland. Design: Qualitative research study involving face to face semi-structured interviews with participants. Setting: A public health directorate in a National Health Service Trust, and a public health demonstration project in child health. Participants: Health promotion specialists, managers, nurses, public health consultants and specialists, researchers, trainees, and other public health staff. Main results: Three main categories of ethical issues were identified: paternalism, responsibilities, and ethical decision making. Consulting with the community and sharing information raised issues of paternalism and honesty. Participants identified multiple and sometimes conflicting responsibilities. Barriers to fulfilling responsibilities included meeting targets, working with partners, and political influences. Defining the limits of responsibilities posed challenges. Participants identified values for ideal decision making, but lack of time often led to a more pragmatic approach. Conclusion: These empirical findings complement and extend existing discussions of public health ethics, emphasising the complex nature of ethical issues in public health. The implications for public health policy and future research are discussed.