This study is an examination of the longitudinal effects of an integrated phonological awareness approach for identical twin boys with childhood apraxia of speech (CAS). Genetic and environmental factors in the boys' responses to the intervention were also examined. Theo and Jamie (aged 4;5) each participated in 18 hours of intervention prior to school entry and were re-assessed at age 4;9, 5;3, and 5;9 respectively. Their speech, expressive morpho-syntactic, phonological awareness, reading, and spelling development were evaluated over their first year of schooling. Theo and Jamie experienced continued growth in speech and phonological awareness skills following participation in the intervention. They exhibited age-appropriate reading and spelling development during their first year of formal literacy instruction. They had persistent deficits in expressive morpho-syntactic skills despite speech production gains over the study. The results pointed to the benefit of integrating speech and phonological awareness goals within a preventative framework to ensure successful early literacy development for children with CAS. Findings suggested that language difficulties in children with CAS should be targeted during intervention as they do not resolve as the children's speech production difficulties minimize.