This article presents a randomized experiment evaluating a computer-assisted tutoring program. The software program, Alphie's Alley, provides reading tutors with assessment and planning tools and performance support. It provides students with animated presentations and engaging activities. In a yearlong study involving 25 schools using the Success for All reading program, 412 low-achieving first graders were randomly assigned to be tutored daily for 20 min with or without Alphie's Alley. Tutors were also randomly assigned. On individually administered reading measures, controlling for pretests, there were no significant differences overall, but among students with tutors rated as "fully implementing," those who experienced Alphie's Alley scored significantly better on three of four measures. These results suggest that if well implemented, technology that enhances the performance of tutors has promise in improving the reading performance of at-risk children. (Contains 2 tables.)