Rapid epidemiological assessment (REA) has evolved over the past 30 years into an essential tool of disaster management. Small area survey and sampling methods are the major application. While REA is protocol driven, needs assessment of displaced populations remains highly non-standardized. The United Nations and other international organizations continue to call for the development of standardized instruments for post-disaster needs assessment. This study examines REA protocols from leading agencies in humanitarian health assistance across an evaluation criteria of best-practice attributes. Analysis of inconsistencies and deficits leads to the derivation of a Minimum Essential Data Set (MEDS) proposed for use by relief agencies in post-disaster REA of health status in displaced populations. This data set lends itself to initial assessment, ongoing monitoring, and evaluation of relief efforts. It is expected that the task of rapid epidemiological assessment, and more generally, the professional practice of post-disaster health coordination, will be enhanced by development, acceptance, and use of standardized Minimum Essential Data Sets (MEDS).