Early diagnosis of children with reading disorders is essential for intervention and academic success. Many children with reading difficulties have a deficit in phonemic awareness. A web-based, group-administered screening vehicle, the Risk Factor Screen for Reading (RiFS-Reading), was developed to quickly identify students who are "At Risk" for reading difficulties by assessing knowledge of phonemic awareness. The goal was to establish the validity of the RiFS-Reading measure. Results supported construct validity through factor analysis and criterion validity by comparisons with performance on well-established measures of phonemic awareness and reading. Phonemic awareness on the RiFS-Reading was independent of other language skills.