Abstract: The study determined the seasonal and spatial variation in the species diversity and abundance of zooplankton fauna in Ede-Erinle reservoir. This was with the view to determining the effects of the physico-chemical characteristics of water on the zooplankton distribution and abundance in the reservoir. A total of 22,628 zooplankters comprising 101 species, 57 genera and five (5) groups (viz. rotifers, cladoceras, copepods, ostracods and dipterans) were collected and identified. The rotifers were the most specious (57 species) while the ostracods were the least (4 species).