Although conventional treatment processes can be effective for the removal for harmful algal bloom (HAB) cells, and for some HAB toxins under optimal conditions, the potential exists for signicant breakthrough of toxins during normal operation. As a result, there is a recognized need for more advanced treatment processes for the treatment of HAB toxins in drinking water. Membrane technologies are increasingly being used for the purication of drinking water, from both freshwater sources and the ocean. As a result, there is interest in understanding the capabilities of these processes for the removal of HAB cells and HAB toxins. The use of membrane processes, alone or in combination with other technology, such as coagulation and powdered activated carbon (PAC), is of increasing interest. Along with more traditional oxidation approaches (e.g., ozone and potassium permanganate), advanced oxidation processes (AOPs) are a promising suite of technologies that offer advantages for the destruction of HAB toxins in drinking water. A number of AOPs are currently under development and examined for destroying HAB toxins, including photolysis, ultraviolet (UV)/H2O2, UV/ TiO2, technologies based on generation of sulfate radical, ultrasound, Fenton reaction, and ferrate. This chapter provides an introduction to membrane and oxidation technologies and their application to removing or destroying HAB toxins in drinking water.