Methods for treating Alzheimers Disease (AD) using modulators of lysosomal activity are described herein. More particularly, methods described herein relate to the use and application of compounds or agents that enhance lysosomal activity for the treatment of AD. In a particular aspect, the method relates to the use and application of compounds or agents that increase the pH of the lysosome and/or increase the overall activity of lysosomal proteases for the treatment of AD. Also described herein are methods and assays for screening to identify compounds or agents that increase the pH of the lysosome and/or increase the overall activity of lysosomal proteases for the treatment of AD.