The number, biomass and diversity of phytoplankton  as well as physico- chemical characteristics of surface water at the three sites (El- Rahawi, El - Serw and  El -Ziaat) representing Delta region of the river Nile were studied in response to discharged liquid wastes from April, 1998 to April, 1999.  A total of 214 algal taxa belonging to 99 different genera were identified. Chlorophyta (81 genera), Bacillariophyta (71 genera), Cyanophyta (28 genera) and Euglenophyta (24 genera) were the dominant group. The minimum phytoplankton growth was in drainage canal of El-Ziaat factory. Moreover, the lower values of diversity and saprobity indicated at drain water concomitant with the higher values of saprobic quotient (SQ) might reflect the pollution status of water.  The physico-chemical assessment of water could point to indicate that the upstream and down-stream water is mesotrophic while, water of the mixed station is eutrophic and at drain station was varied between eutrophic to hypereutrophic conditions. Moreover, the low pH values at discharged waste of Soda factory at El-Ziaat and the undetectable dissolved oxygen at El -Rahawi drain were considerably retracted at the mixed and more at down-stream water.