The process of drying the cassava root into a flour yields a liquid waste, which is toxic to water and soil. Alternative solutions are being developed in order to valorize this material and preserve the environment. Cassava wastewater is being studied for its potential as a carbon source for production of various substances through fermentation. This work aims to investigate the tolerance of yeast species to cassava wastewater. Five yeast species were tested. Biomass production and reducing sugars consumption were evaluated in order to estimate microbial growth. The yeast species tested so far have shown tolerance to the substrate, and may present potential for ethanol production through fermentation using cassava wastewater as substrate.