Coleoptera in flood debris are involved in several apparently disparate, but ultimately interrelated disciplines. In some situations, more than 100 beetle species have been collected from debris immediately after a flood and can greatly augment a biotic survey. Beetles entrained in floods represent an important component of terrestrial inputs into lotic systems. Many species of beetles have evolved morphological and behavioral adaptations to avoid or exploit the costs and benefits of flooding and are dependent on floods for habitat formation in the aquatic/terrestrial transition zone along rivers. Quaternary beetle fossils, often found in fluvial deposits, offer a powerful tool to reconstruct past climates and ecosystems, and an important way to better understand the history of a species' distribution. However, the categories above are artificial and overlapping. With rare exception, studies linking these disciplines could not be found. For example, by studying beetles in flood debris today, paleontologists can personally witness the creation of a thanatocoenosis (death assemblage) produced by the same process acting on the same species that left fossils 100,000 years ago. Continued study of the interaction of beetles and floods, especially in light of global climate change, carries the potential to better predict ecosystem-wide changes in the near future.