From late spring through to autumn cyanobacterial blooms are a common feature of reservoirs and river weir pools throughout Australia. While usually not large in comparison with eutrophied European water bodies - biomass peaks of 10-30 µg chl a L-1 are typical - these blooms are wide spread; from the tropical and sub-tropical zones in the north of the continent to the warm temperate and arid regions in the south. The moderate size of the blooms reflects the fact that anthropogenic nutrient inputs to waterways are lower than in other parts of the world where human population densities far exceed those of inland Australia. As in the cooler parts of the world, the dominance of the freshwater phytoplankton by cyanobacteria for several weeks or months each year is related to the onset and persistence of thermal stratification. In Australia’s hot arid climate the period of stable stratification in reservoirs and slow-flowing rivers may last for 9-10 months of the year. Combined with the high net solar insolation, this provides conditions that are ideal for buoyant cyanobacteria. This selective pressure is further enhanced in our clay-turbid rivers where photic zone depths are often less than 1-2 metres. Bloom frequency also shows a climate related inter-annual variability coupled to variations in the El Nino-Southern Oscillation (ENSO). Other factors, particularly those relating to reservoir food web structure and imbalances, may also contribute to the dominance of cyanobacteria. Recent work by CSIRO has shown that the excessive populations of planktivorous fish found in Australian reservoirs may stimulate a high phytoplankton biomass and favour cyanobacteria over other phytoplankton. The management of cyanobacterial blooms in Australia has developed rapidly during the past decade. There has been a broadening of the managerial focus from a single-pronged strategy addressing only the control of catchment nutrient inputs, to a strategy which combines catchment management with in-reservoir techniques such as destratification, sediment remediation, biomanipulation, and flow-regulation of rivers. Whether these approaches will ultimately be successful, or whether Australia’s climate is too great an obstacle to cyanobacterial bloom management is yet to be seen. At the downstream‚ consumer end, management actions have focussed on refinements to drinking water treatment processes to ensure removal of cyanobacterial toxins.