The zooplankton populations play a vital role in food web, food chain in nutrient recycling and transfer of organic matter from primary producers to secondary consumers in freshwater. The seasonally variations of fresh water zooplankton were investigated from Wellington Lake, Cuddalore district of Tamil Nadu, India. The sampling was carried out from January 2016 to December 2016. In the present investigation, totally 24 species of zooplankton from 4 taxa were identified along with Rotifers (10), Copepods (9), Cladocera (4) and Ostrocoda (1). The rotifer was dominant groups of total zooplankton. The descending order of abundance in the various groups of zooplankton is as follows: Rotifers > Copepods > Cladocera > Ostrocoda. The maximum of population density was reported in post monsoon season and minimum was reported in monsoon season during the study period. It was concluded that the seasonally variations of fresh water zooplankton was also influenced by physicochemical parameters.