BACKGROUND: Depression occurs in up to 50% of patients after stroke and limits rehabilitation and recovery. Mood disorders are also highly prevalent in carers; their mental health intertwined with the physical and mental wellbeing of the person they are caring for. We argue that working with families, rather than patients alone may improve the treatment of depression in both patients and their carers enhancing the mental wellbeing and quality of life of both. METHODS: A single blind cluster randomised controlled trial to evaluate whether families after stroke who are treated with the Depression Recognition and Treatment package (DepReT-Stroke) in addition to treatment as usual (TAU) show improved mental well being compared to those families who receive only TAU. We aim to recruit one hundred and twenty-six families (63 in each group). The DepReT-Stroke intervention will help families to consider the various treatment options for depression, make choices about which are likely to fit best with their lives and support them in the use of self-help therapies (e.g. computerised Cognitive Behavioural Therapy or exercise). An essential component of the DepReT-Stroke package will be to help people adhere to their chosen treatment(s). The primary outcome will be the Mental Component Subscale of the SF-36 assessed at baseline and again six months post intervention. Effectiveness of the intervention will be determined using analysis of co-variance; comparing the mean change in MCS scores from baseline to six months follow-up adjusting for the clustering effects of baseline scores and family. An economic evaluation of the intervention will help us determine whether the intervention represents a cost-effective use of resources. DISCUSSION: Depression both for patients and their carers is common after stroke. Our Depression Recognition and Treatment package (DepReT-stroke) may help clinicians be more effective at detecting and managing a common co-morbidity that limits rehabilitation and recovery. TRIAL REGISTRATION: ISRCTN: ISRCTN32451749 Research Ethics Committee Reference Number: 10/H0310/23 Grant Reference Number: (NIHR) PB-PG-0808-17056.