This study was carried out in Nozha hydrodrome, Alexandria, to assess the impact of physico-chemical parameters upon zooplankton community structure and diversity during the period from December 2015 to November. 2016. The results indicated that there were significant monthly variations in physical and chemical characteristics, such as water temperature, pH, dissolved oxygen, total alkalinity, total hardness, nitrite, nitrate, total nitrogen,orthophosphate and total phosphorus. Zooplankton were represented by fifteen genera belong to four groups. Rotifera constituted the main dominant group contributing 82.59% of the total zooplankton, followed by Copepoda (12.33%), Cladocera (3.886%) and Ostracoda (1.22%). The highest density of zooplankton was recorded during January (mean 2504.5 org/ l), while the lowest was found in July (mean 44.25 org/l).The data pointed out that the most effective water variables on composition and distribution of zooplankton were water temperature, total alkalinity, total hardness, ammonia, nitrite, nitrate and total nitrogen. The low value of Shannon diversity index, high value of some water parameters and dominance of pollution tolerant forms of zooplankton revealed that the hydrodrome is suffering from organic pollution.