Health researchers, research trainees, and ethics reviewers should be prepared for the special application of research ethics within complex humanitarian emergencies. This paper argues that as a precursor to published ethical guidelines for conducting research in complex emergencies, researchers and research ethics committees should observe the following primary ethical considerations: (1) the research is not at the expense of humanitarian action; (2) the research is justified in that it is needs-driven and relevant to the affected populations; and (3) the research does not compromise the humanitarian principles of neutrality, impartiality and independence. These primary considerations are in harmony with the humanitarian goals of saving lives, alleviating suffering, and témoignage. Furthermore, there is an important role for research in supporting humanitarian action, and the extreme vulnerability of research participants in complex emergencies demands intense research ethics scrutiny. It is important to discern which ethical considerations are essential, and which are merely desirable, as excessive research ethics requirements may impede life-saving research.