A survey of the aquatic and semi-aquatic insect fauna of a semi-tropical, arid zone oasis on the western Dead Sea coast, was conducted primarily in the summer and winter seasons of 1980/81. A table is given of the aquatic entomofauna, including their zoogeographical affinities, Israeli distribution and presence in En Gedi and in each of the two canyons there. Zoogeographical analysis reveals a predominance of tropical and arid African affinity (Ethiopian = 31%, Saharo-Arabian = 19%), with a major affinity also to the Mediterranean (21%). The entomofaunal community was divided among seven ecological biotopes: fast or slow flowing streams and pools; eddies; bedrock or deep pools; standing or stagnant pools. A community analysis table of the occurrence of the major faunal elements in each of seven biotopes is presented. Some rather stenotopic taxa were indicative of biotopes. A comparison is made of summer and winter seasonality including the effects of flash floods and the relation of these phenomena to emigration/imigration and life cycles of the entomofauna. The effects of agriculture and tourism are discussed and proposals made for conservation of the biotope communities. These biotopes and their entomofaunal communities are presumed to represent most of the habitats of Middle East arid zone springs.