Inter-agency coordination in humanitarian assistance dates as a discipline from the 1960s. The United Nations, Red Cross, governmental, and non-governmental agencies have evolved different mechanisms to achieve it. Present practices in field-based, inter-agency coordination of the health sector remain variable and non-standardized. International experiences in coordination of humanitarian assistance reveal numerous issues of jurisdiction, authority, capacity, and competency. New tools to help overcome these issues in the health-sector coordination include binding principles of engagement, protocols for the assumption of responsibilities, standardized minimum essential data sets, and health-sector component summaries.