Based on the recent international publications, this study explained the modification of taxonomic name in three common phytoplankton genera. The new classification systems of Oscillatoriales and Bacillariophyceae were also introduced. According to the taxonomy of Anagnostidi & Komárek (1988), the former cyanobacteria genus Oscillatoria was split up. Most of the planktonic species of this group can now be found in two new genera Planktothrix and Limnothrix. About 70 other species in this group were shifted into the genus Phormidium. According to the taxonomy of Kramme and Lange-Bertalot (1991), all the planktonic species of the former diatom genus Melosira formed a new genus Aulacoseira. Some other species in this group were moved into the genera Orthoseira and Ellerbeckia. Most of the planktonic species of the former diatom genus Synedra were altered back to the genus Fragilaria. Some other species can now be found in the genera Nitzschia and Hantzschia.