BackgroundThis protocol describes a study of the effectiveness of cognitive behaviour therapy (CBT) for reducing depressive symptoms in older adults living in residential aged care (RAC) facilities in Australia. Depressive symptoms are highly prevalent in this population, yet the benefits of CBT for reducing such symptoms in RAC facilities have not been widely investigated. Elders at Ease (ELATE) is a 16-session CBT intervention designed for implementation in RAC facilities. The intervention includes cognitive, behavioural and reminiscence strategies and is delivered by mental health trainees (MHTs) in collaboration with RAC facility staff and residents’ family.Methods and analysisELATE will be evaluated using a cluster randomised trial comparing outcomes for residents who participate in the intervention with those living in usual care control facilities. The participants are RAC residents aged 65 years or above, with depressive symptoms (Patient Health Questionnaire-2 ≥ 3) and normal cognition or mild cognitive impairment (Standardised Mini Mental Status Examination ≥ 21). They are assessed at four time points: baseline prior to randomisation (T1), mid-treatment (T2; 2.5 months post randomisation), post-treatment (T3; 5 months post-randomisation) and 3-month follow-up (T4; 8 months post randomisation). The primary outcome is change in depressive symptoms between T1 and T3. Secondary outcomes are depressive symptoms at T4, anxiety, suicide ideation, sleep problems, quality of life, staff and family knowledge of late-life depression, stress levels and efficacy in caring for residents, and MHT levels of geropsychology competencies. Residents receiving the intervention are hypothesised to report a greater decrease in depressive symptoms between T1 and T3 compared to residents receiving usual care. The primary analysis is a regression, clustered over site to account for correlated readings, and independent variables are condition and depressive symptoms at T1. A cost-utility analysis is also undertaken.DiscussionELATE is a comprehensive CBT intervention for reducing depressive symptoms in RAC residents. It is designed to be implemented in collaboration with facility staff and residents’ families, individually tailored to residents with normal cognition to mild cognitive impairment and delivered by trainee therapists. ELATE offers a model that may be widely applicable across the RAC sector.Trial registrationTrial registered with the Australian and New Zealand Clinical Trial Registry (ANZCTR) Number ACTRN12619001037190, prospectively registered on 22 July 2019.