Background: Children with Down syndrome experience difficulty with both spoken and written language acquisition, however controlled intervention studies to improve these difficulties are rare and have typically focused on improving one language domain. Aims: To investigate the effectiveness of an integrated intervention approach on the speech, letter knowledge, and phonological awareness development of ten pre-school children with Down syndrome aged between 4;4 and 5;5. Methods and Procedures: A multiple single-subject design was used to evaluate treatment effectiveness. Baseline and intervention measures for speech and pre- and post-intervention measures for letter knowledge and phonological awareness were compared. The intervention comprised three components: a parent-implemented home programme; centre-based speech-language therapy sessions, and 'Learning through Computer' sessions with a total intervention time of 20 hours over 18 weeks. Letter knowledge and phonological awareness activities were linked to each child's speech targets. Outcomes and Results: Results indicated significant treatment effects on speech measures for all ten participants. Six of the ten participants showed increases on letter knowledge and nine showed increased awareness of initial phonemes in words but responses were not above binomial chance level (that is, 70% correct) for phonological awareness tasks. Individual results are presented and implications for parents and therapists are discussed. Conclusions and Implications: The findings of this study suggest an intervention approach that integrates speech, letter knowledge, and phonological awareness targets is effective in remediating speech error patterns at the single-word level in young children with Down syndrome. Phonological awareness and letter knowledge appeared to be stimulated through the intervention, but significant improvement above chance levels on untrained phonological awareness tasks was not evident. Follow-up investigation is necessary to determine longer-term outcomes.