Heavy spring and summer rains during 1993 caused flooding by both the Mississippi and Missouri rivers and by streams in 84 of the 115 counties in Missouri; all 84 were declared federal disaster areas. The Mississippi River attained flood stage during July 15-August 2, and the Missouri River, during July 25-August 2; a total of 2,060,757 acres were submerged, and approximately 60,000 persons throughout Missouri were displaced (National Weather Service, unpublished data, 1993). At the request of the Missouri Department of Health, CDC provided assistance in implementing a surveillance system to monitor flood-related injuries and illnesses in the affected areas. This report presents preliminary findings of these surveillance efforts.