Research articles in the reference list regarding investigation or exploration of Oscillatoriales exhibited that taxonomic study of freshwater blue-green algae has been a subject of interest of research workers and professional scientists for more than one century in India. Oscillatoria Vauch. ex Gom. (Cyanoprokaryota: Oscillatoriales) is a dominant and ubiquitous blue-green alga in Hooghly District of West Bengal, India. Its thallus is consists of unsheathed trichome and contains more than 20 cells in a trichome. The recent study was dealt with the taxonomic enumeration of five species of the genus (O. princeps, O. curviceps, O. sancta, O. limosa, and O. jenensis) which were collected from different freshwater aquatic ecosystems of this district and they were described with ecological data, geographical distributions and colored microphotographs. Here, the relationships between the water chemistry and their occurrences had been also discussed. The analysis of important physico-chemical properties of water revealed that species of Oscillatoria prefer to grow in those water bodies prevailing alkaline pH, sufficient to meet the essential nutrients and contain hard and polluted water.