Rapid Ethical Assessment is an approach used to design context tailored consent process for voluntary participation of participants in research including human subjects. There is, however, limited evidence on the design of ethical assessment in studies targeting cancer patients in Ethiopia. REA was conducted to explore factors that influence the informed consent process among female cancer patients recruited for longitudinal research from Addis Ababa Population-based Cancer Registry. Qualitative study employing rapid ethnographic approach was conducted from May–July, 2017, at the Tikur (...) Anbessa Specialized Referral Hospital. In-depth and key informants’ interviews were conducted among purposively selected 16 participants. Regular de-briefings among the study team helped to identify emerging themes and ensure saturation. Interviews and debriefings were tape recorded in Amharic, and transcribed and translated to English. Coding of the transcripts was facilitated by use of NVivo software. Thematic analysis was employed to respond to the initial questions and interpret findings. Perceived barriers to voluntary study participation included lack of reporting back study results of previous studies, the decision making status of women, hopelessness or fatigue in the patients, shyness of the women, data collectors approach to the patient, and patient’s time constraints. Most of the patients preferred oral over written consent and face-to-face interview over telephone interview. Provision of detail information about the study, using short and understandable tool, competent, compassionate and respectful enumerators of the same gender were suggested to assure participation. Due to the perceived severity, the use of the term “cancer” was associated with fear and anxiety. Alternatively, uses of phrases like “breast or cervical illness/disease” were suggested during patient interviews. Voluntary participation is not straight forward but affected by different factors. Using competent, compassionate and respectful enumerators, short and precise questioning tools to limit the time of the interview could improve voluntary participation. Moreover, careful consideration of the patients and families concept of the disease such as wording and information has to be taken into account. This assessment helped in improving the consent process of the ongoing project on breast and cervical cancer patients. (shrink)