Background/Aims: Chronic post-stroke aphasia impacts 30% of stroke survivors. The aim of this trial is to determine whether two contrasting, intensive treatments, Constraint Induced Aphasia Therapy (CIAT) and Multi-Modal Aphasia Therapy (M-MAT), are superior and cost-effective than usual care (UC). The variable response to these therapies may be accounted for by aphasia severity and co-occurring cognitive problems. Methods: 3-arm prospective, single-blinded, randomised controlled trial. Primary end point at 3 months post-treatment. Participants (n = 198) are randomised to CIAT, M-MAT or UC. CIAT and M-MAT both focus on intensive speech practice (30 hours over 2 weeks) using interactive game formats. However, while M-MAT involves gesture, writing, and drawing cues, CIAT focuses on speech alone. UC is usual health service-based aphasia therapy. Primary outcome immediately post treatment is the Aphasia Quotient of the Western Aphasia Battery. Secondary outcomes at 3-month follow-up include measures of connected speech, multi-modal communication, and quality of life. Participant cognitive and linguistic predictors of treatment response are identified. Re-randomised UC participants will undertake a less intense schedule (30 hours over 5 weeks) in a nested sub-study exploring the impact of treatment intensity on outcomes. A full cost-effectiveness analysis will be undertaken. Results: The trial is underway: ethics approval, trial registration, and database are established. Recruitment from five Australian states has commenced. Conclusions: This trial will determine if there is a significant therapeutic effect of, and variable response to treatment types in chronic aphasia. Essential economic evaluation information for service delivery standards for aphasia rehabilitation will be described.