In spite of its ubiquitous occurrence our knowledge about Cyanoprokaryotes of tropical countries is not proper (Kom__ampersandsignaacute;rek and Anagnostidis 2005). Oscillatoria Vaucher is the most ubiquitous genus of Oscillatoriales of Cyanoprokaryota growing in almost all accessible habitats starting from hot springs to snow-fed rocky areas. Its adaptability to different climatic conditions is marvelous. In India Oscillatoria Vaucher is represented by over 76 species (Desikachary 1959, Anand, 1989, 1998). During systematic investigations on the algal flora of West Bengal the authors recorded following species of Oscillatoria viz O. obscura Br__ampersandsignuuml;hl et Biswas, O. sancta (K__ampersandsignuuml;tzing) Gomont, O. simplicissima Gomont, O. anguina (Bory) Gomont, O. subbrevis Schmidle, O. nitida __ampersandsignScaron;korbatov, O. proboscidea Gomont, O. tenuis Agardh ex Gomont, O. salina Biswas, O. princeps Vaucher ex Gomont, O. raoi DeToni, J., O. limosa Agardh ex Gomont, O. amoena (K__ampersandsignuuml;tzing) Gomont, O. vizagapatnesis Rao, C.B., O. okeni Agardh ex Gomont and O. laete-virens (Crouan) Gomont. The distributions of different species have been discussed. O. simplicissima, O. princeps, O. subbrevis, O. sancta and O. tenuis are most common species in unpolluted habitats where as O. limosa is common in polluted habitats. O. nitida appears to be the first Cyanoprokaryote recorded in India.