The use of epidemiology in documenting the mortality experience in complex emergencies has become pervasive in humanitarian practice. Recent assessments in Iraq and Darfur have provoked much discussion on the assessment of mortality in scientific and policy spheres. In this context, the Centre for Research on the Epidemiology of Disasters and the Harvard Humanitarian Initiative held an inter-disciplinary symposium to examine the topic among epidemiologists, demographers, forensic scientists and legal and human rights investigators.We aimed to strengthen the scientific understanding of mortality estimation by reviewing progress across fields and building inter-disciplinary bridges. We report on the presentations and discussions here.