Cyanobacteria are morphologically diverse group of pioneer oxygenic phototrophic prokaryotes with characteristics in common to both bacteria and algae that originated 3.5 billion years ago and distributed in all possible biotopes of the world. They are ubiquitous found in clean and polluted waters of lakes, ponds and reservoirs, in fresh or salt waters and in stagnant or flowing waters. Whereas some cyanobacteria are unicellular, others grow as chains of cells termed trichome's or filaments. Bidhannagar subdivision is a high density of population around 6,500/km2, situated in the district of North 24 Parganas, West Bengal with a vast area of about 33.10 km2 and giving rises many freshwater ponds, drains and canals which are the main reservoirs of different types of microalgae and cyanobacteria. An attempt has been made to study the diversity of nonheterocystous filamentous cyanobacteria from freshwater bodies of Bidhannagar subdivision in the district of North 24 Parganas, West Bengal (Figure 1 A- C). During this investigation around 140 samples were collected randomly from free floating and stagnant freshwater ponds, drains and canals of different municipalities (Figure 1C-G) during the year 2019. In this study altogether 32 non-heterocystous filamentous cyanobacterial forms belonging to 4 genera were characterized and enumerated (Figure 2-3 and Table 1). Most of them occur in free floating, submerged and attached forms (Figure 1D-G). The most common and dominant cyanobacterial genera were Oscillatoria representing 28 species followed by Spirulina 2 and Phormidium, Lyngbya each with 1 species.