This paper has been published in Peer-reviewed International Journal "Shrinkhla Ek Shodhparak Vaicharik Patrika" URL : http://socialresearchfoundation.com/new/publish-journal.php?editID=9254 Publisher : Social Research Foundation, Kanpur (SRF International) Abstract : Water bodies are polluted by variety of pollutants released from activities, like, mining, energy generation, urban waste disposal, agricultural and industrial discharge or crude oil/fuel exploration and refining. These pollutants can be poisonous, mutagenic, carcinogenic, terratogenic as well as bioaccumulative and need to be treated. Their eco-friendly treatment is the need of the hour. Cyanobacterium could be a potential option for waste water treatment. Their dominance and survival ability in a variety of habitats from saline or acidic condition to hot springs and extremely low temperature habitats along with their nutrient utilization and contaminant removing capability make them useful in waste water treatment. This review is an attempt to summarize the role of cyanobacteria in bioremediation of polluted water.