**Objectives:** Recent preliminary evidence suggests that mindfulness-based programmes may be beneficial in the treatment of patients suffering from current depression. Due to the heterogeneity of patients with this diagnosis, a specialisation in treatment concepts for subgroups of patients may be beneficial. **Methods:** This randomised controlled pilot study investigated the effectiveness of an eight-week mindfulness-based day hospital treatment for patients with current depression and work-related conflicts (MDT-DH) under naturalistic conditions. Eighty-one currently depressed patients with work-related conflicts were randomly assigned to either MDT-DH (including personalised psychopharmacological treatment if necessary) or a waitlist condition including a psychopharmacological consultation (PCC). Outcomes were assessed at post-treatment and at 8-month follow-up. The primary outcome was depression severity (Beck Depression Inventory) at post-treatment. Secondary outcomes were work ability (Work Ability Index) and mindfulness (Kentucky Inventory of Mindfulness Skills). **Results:** A multilevel analysis revealed that compared to patients in PCC, patients in the MDT-DH group showed a greater reduction in depression severity, higher work ability, and heightened levels of mindfulness after eight weeks than patients in the PCC group. These improvements were stable during the 8-month follow-up period. **Conclusions:** Findings of the present pilot study suggest that a treatment concept involving intensive training in mindfulness can be successfully established in a day hospital and leads to clinically meaningful reductions in depression severity and increases in work ability in patients suffering from current depression. The generalisability of the findings may be limited due to small sample size, selective patient group, and study design. **Keywords:** mindfulness, RCT, depression, work ability, work-related stressors, day hospital **Data:** Data available for the following article: Buxton, A. E., Remmers, C., Unger, H.-P., Plinz, N., & Michalak, J. (2020). Treating Depression Mindfully in a Day Hospital: a Randomised Controlled Pilot Study. Mindfulness, 11(2), 384-400. doi:10.1007/s12671-019-01233-4