The Picture Exchange Communication System (PECS) is an augmentative and alternative communication program (Frost & Bondy, 2002). Although PECS has been effectively used to teach functional requesting skills for children with autism, mental retardation, visual impairment, and physical disabilities (e.g., Anderson, Moore, & Bourne, 2007; Chambers & Rehfeldt, 2003), there are limited studies examining the effectiveness of PECS to teach requesting skills for children with multiple disabilities including visual impairment (Lund & Troha, 2008). This study explored the effectiveness of combining tangible symbols and other adaptations with PECS to teach requesting skills to students with multiple disabilities. Specifically, the participants were four students with multiple disabilities including visual impairment who also had many challenges in communication skills. The research design was the multiple probe design across subjects, a variation of a "multiple baseline" design. A notable benefit to this design is that there was no need to collect continuous recordings of baseline measures, because a strong "a priori" assumption of stability and the possibility of causing strong participant reactions existed before introducing the intervention. Instead, the researcher made periodic recordings of baseline levels to insure no significant changes have occurred before introducing the intervention. The study included four parts: (a) the assessment of reinforcers, (b) baseline, (c) the implementation of the intervention, which was teaching the three PECS phases and conducting generalization sessions, and (d) the maintenance condition. Three important research questions were posed: (1) Can students with multiple disabilities including visual impairment learn to make requests for preferred items using adapted PECS materials and procedures? (2) Can students with multiple disabilities including visual impairment generalize requesting skills for preferred items using adapted PECS from training rooms to classrooms? (3) Can students with multiple disabilities including visual impairment maintain requesting skills after training? The results indicated that all four participants learned requesting skills using adapted PECS, generalized the newly acquired skills to their classrooms, and maintained the requesting skills after training. Results of this study provided preliminary evidence that PECS with adaptations could be used effectively to teach requesting skills for students with multiple disabilities including visual impairment. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]