Due to its unprecedented scale, the Pakistan flood disaster tested the limits of disaster management and coordination. Under the leadership of the World Health Organization, the Global Health Cluster system for coordinating activities improved collaboration and efficiency in conducting rapid needs assessments. However, the involvement of non-Cluster members was lacking, and information on existing service provision was not collected adequately. The present rapid health needs assessment process under the Cluster system will be discussed, using the recent floods in Pakistan as an example.