Do not resuscitate (DNR) decision making is an integral component of emergency medicine practice. There is a paucity of data, protocols and guidelines regarding the perceptions and barriers that are involved in the interactions among healthcare professionals, patients and their caregivers regarding DNR decision making. The aim of this study is, therefore, to explore the perceptions and factors influencing DNR decision making in the emergency department and to evaluate the use of a context-based protocol for DNR decision making. This will be a sequential mixed method study beginning with qualitative research involving in-depth interviews (IDIs) with patient family members and focus group discussion with healthcare professionals. The consensual qualitative approach will be used to perform a thematic analysis to the point of saturation. The expected outcome will be to identify key themes that suggest perceptions and factors involved in DNR decision making. After piloting, the derived protocol will then be used with a different group of individuals (150 healthcare professionals) who meet the eligibility criteria in a quantitative cross-sectional study with universal sampling. Data will be analysed using NVIVO in the qualitative phase and SPSS V.19 in the quantitative phase. The study findings will support the development of a standardised protocol for DNR decision making for healthcare professionals in the emergency department. The proposal was reviewed by the ethics review committee (ERC) of the institution (ERC # 2020-1551-7193). The project is an institution SEED grant recipient PF139/0719. The results will be disseminated among participants, patient communities and healthcare professionals in the institution through seminars, presentations, brochures and emails. The findings will be published in a highly accessed peer-reviewed medical journal and will be presented at international conferences. © Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.