Halda River is a renowned natural spawning ground of major carps due to the unique physicochemical and biological properties of its water. The productivity of the Halda ecosystem depends mainly on plankton diversity. A 2- year- study was conducted (Jan. 2017- Dec. 2018) to identify the phytoplankton community of the Halda River. A total of 74 species of phytoplankton were recorded, which represent 47 genera and belong to 8 classes. The dominant class of phytoplankton was 28 species of Bacillariophyceae (37.84%) followed by 14 species of Zygnematophyceae (18.92%), 8 species of Chlorophyceae (10.81%), 10 species of Cyanophyceae (13.51%), 9 species of Euglenophyceae (12.16%), 3 species of Dinophyceae (4.05%),  1 species of Ulvophyceae (1.35%), and 1 species of Trebouxiophyceae (1.35%). Thus, the River Halda is a productive water body with diversified groups of phytoplankton.