A single subject multiple probe across subjects research design was used to evaluate a writing instructional program for children who use augmentative and alternative communication (AAC). Specifically, the effect of instruction on the selection of initial letters of words by 3 children with developmental disabilities who used AAC was evaluated. The writing instructional program comprised direct instruction in letter-sound correspondence and selection of initial letters of words, and a writing workshop-type task to provide instruction in literacy activities. Two of the 3 children were successful in the acquisition of the target skill, maintained use of the skill at least 1 month following instruction, and demonstrated some generalization of the skill to less structured tasks. The third child required a simplified instructional program to accommodate transient episodes of hemiplegia and to increase his time on task. The results of the study suggest that an instructional program that combines a direct instruction approach and a writing workshop-type activity may facilitate the development and application of phonemic awareness skills with children who use AAC.