The biomonitoring of water quality in Bhadrakali lake Warangal, was assessed by using Odum's algal index in four sites during October 2004 to September 2005.The higest range of Odum's algal index was in between 300 to 400 with Microcystis, Nodularia, Trichodesmium, Chlamydomonas, Cladophora, Spirulina. With this, we can establish phytoplankton as efficient biological pollution indicator for monitoring the water quality in Bhadrakali lake.