Background: Compassion plays a significant role in caregiving and its benefits have been largely reported in different settings. Nonetheless, compassion-based interventions have not yet been delivered to Residential Youth Care (RYC) staff. Objective: This study presents early findings of a Cluster Randomized Trial on the efficacy of a Compassionate Mind Training program for caregivers of RYC (CMT-Care Homes) following CONSORT guidelines. Participants and setting: Participants were 85 caregivers (89.4% female), aged between 25 and 62 years old, working on a regular basis with adolescents in RYC. Method: Eleven Portuguese residential care homes for at-risk adolescents were selected and randomly allocated to the treatment (n = 5) or control (n = 6) conditions. Caregivers were assessed at pre- and post-intervention (n = 41 treatment, n = 44 control) through self-report scales on compassion and emotional climate related outcomes. Results: To investigate CMT-Care Homes effects, a two-factor mixed MANOVA was performed. Multivariate tests showed a significant and large Time x Group interaction effect (Pillais' trace = 0.291, F = 2.719, p = .005, eta(2)(p) = 0.291). Univariate tests indicated significant and positive effects in compassion and fears of compassion (low and medium effect sizes), as well as in soothing related emotions (emotional climate) and social safeness (both with medium effect sizes), in favor of the treatment group. Conclusions: Findings offer preliminary evidence of the effectiveness of the CMT-Care Homes program, suggesting that this training allows the development of an affiliative mentality in caregivers working within RYC settings.