The present study was carried out in Lake Manzala to follow up the physico-chemical parameters, prevalence and biodiversity of the zooplankton particularly protozoan organisms. Organisms were sedimented by using cold centrifugation technique at 7^oC followed by examining and counting via Carl-Zeiss Jena transmitted-light inverted microscope. Protozoa represented the most common zooplankton where ciliates predominate flagellates which are followed by sarcodines. It was proved that the pollution level of this lake is much higher than those of the Nile branches which could be referred to the extensive illegal discharges of various pollutants from more than five provinces, those of oil pollutants derived from Mediterranean sea and sewage discharges. Comparing the present data with the previous records, it appears that a peculiar achievements was obtained at the moment, but still need more urbanization to have more progress from the ecological and economic points of view.