Cyanobacterial diversity occurring in some local rice fields of Cuddalore District of Tamilnadu, India has been studied. 25 taxa belonging to 10 genera were obtained and characterized are non-heterocystous, unicellular, colonial and filamentous forms. This study is aimed to describe the abundance of cyanobacteria in various rice fields of Vallampadugai and Keerapalayam areas. This paper documented total of 25 species representing 10 genera of 2 families and 2 orders. Highest abundance of cyanobacteria was found in order Nostocales which was represented by 17 species. Morphological features were described for each species systematically. The present study indicates ubiquitous distribution of cyanobacteria in rice fields and could be exploited for biofertilizer in agriculture.