The current study was organized to identify the phytoplankton at four sites of the East Hammar Marsh (Al-Sada, Al-Mansoury, Al-Dawody and Al-Baraka) from December 2019 to November 2020. Upon examining 135 phytoplankton species (non-diatom), it was noticed that 70 Chlorophyta species belonged to 27 genera (52%), 38 Cyanophyta (cyanobacteria ) species belonging to 15 genera (29%), 12 Euglenophyta ( Euglenozoa ) species belonging to three genera (9 %), eight charophyta species belonging to two genera (6%), four Dinophyta (Miozoa )species belonging to three genera (3%) and two Chrysophyta (Ochrophyta) species belonging to two genera (1%) were detected. In addition, five new species were recorded in Iraqi algal flora, two of which are Cyanobacteria. Chroococus mipitanensis and Gomphosphaeria semen-vitis are all species of the Cyanophyceae class. Moreover, the study identified two species; namelt, Tetrastrum heteracanthum (class Chlorophyceae) and Dicloster acuatus (class Trebouxiophyceae) belonging to Chlorophyta, as well as one species from Ochrophyta, Dictyocha fibula (class Dictyochophyceae). On identifying the algal flora (phytoplankton) in the East Al-Hammar Marsh after it was forced dry (during the 1990s) and flooded in 2003, it was found that the ecosystem's characteristics changed, and some species disappeared while others arose.