Purpose: Speech--Music Therapy for Aphasia (SMTA), a method that combines speech therapy and music therapy, is introduced as a treatment method for childhood apraxia of speech (CAS). SMTA will be evaluated in a proof-ofprinciple study. The first case study is presented herein. Method: SMTA was evaluated in a study with a single-subject experimental design comparing 10 weeks of treatment with 2 months of no treatment. The research protocol included a pretest, baseline phase, treatment phase, posttest, no-treatment phase, and follow-up test. The participant was a boy with CAS aged 5;8 (years;months). Outcome measures were selected to reflect both intelligibility in daily communication as well as features of CAS and speech motor planning and programming. Results: Results on the Intelligibility in Context Scale--Dutch (ICS-Dutch) and in the analysis of a spontaneous speech sample suggest generalization of treatment effects. Improvements were found in measures that reflect complex speech motor skills, that is, the production of consonant clusters and consistency. Conclusions: This case study showed that speech production of the participant improved after treatment with SMTA. Although intelligibility as measured with the ICS-Dutch improved over the study period, objectifying changes at the level of intelligibility in daily communication proved to be difficult. Additional measures may be necessary to gain more insight into treatment effects at this level. Overall, the results of this first case study provide sufficient support and important leads for further evaluation of SMTA in the treatment of CAS in a proof-of-principle study.