Abstract: The present study focused on the extraction of cyanobacterial exopolysaccharides and their utilization as a bioflocculant. A cyanobacterium, Phormidium sp., was chosen based on the production of Extracellular Polymeric Substances (EPS). Later it was identified as Phormidium persicinum by 16S rDNA gene sequence and sequences were deposited in GenBank with accession number KC 859032. EPS was extracted from this strain using standard precipitation method. It was found that EPS production was maximum at late log phase of cyanobacterial growth (20 days). HPLC analysis revealed that presence of sucrose as a major component in the extracted EPS. Interestingly, the extracted EPS was found to be a good bioflocculant even at very low concentration (10 mg L-1). Cyanobacterial based EPS showed potential bioflocculation which can be directly utilized for the water purification and refining processes.