Evaluating the coordination of humanitarian actors within the response tothe tsunami of December 2004 provides anopportunity to reflect on the behaviour andperformance of the international responsesystem when, unusually, financialresources were not a constraint. This evaluation covers three countries:Indonesia, Sri Lanka and the Maldives, withsome additional observations from Thailand. The evaluation focuses on the efficiency,effectiveness, coherence and appropriateness of coordinationarrangements within the internationalhumanitarian system and how this relatedto national government and non-governmentalagents. The analysis, drawnfrom a working definition of coordinationand its systems and tools, embodies eightthemes:1) leadership and management ofrepresentative bodies, 2) negotiation and maintenance of aserviceable framework with hostpolitical authorities, 3) promotion of a functional division oflabour (including civil–military), 4) strategic planning, 5) mobilization of resources for integrated programming, 6) gathering data and managinginformation, 7) accountability (including accountabilityto recipient populations) and 8) joint advocacy.