This Phase I project develops and evaluates a mobile application for teaching elementary and middle school aged children with intellectual and developmental disabilities toilet training skills. A team of educational experts, technology experts, and parent of a child with autism collaborate on the project to ensure the mobile application has the greatest benefit. Specific goals include: (1) developing a fully functioning mobile application with visuals, media, and touchable interface; and (2) verifying through a single subject design the mobile application teaches toilet training to three children with developmental disabilities ages 6 through 15. Additionally, this study contributes to disabilities research on toilet training and the use of mobile devices for instruction. Descriptors: Autism, Children, Community living, Daily living, Developmental disabilities, Intellectual Disabilities