Background Individuals who were maltreated during childhood are faced with increased risks for developing various psychological symptoms that are particularly resistant to traditional treatments. This pilot study investigated the effects of a mindfulness based behavioral intervention for young adults with a childhood maltreatment history. Methods This study looked at self-report psychological questionnaires from 20 subjects (5 males) before and after a mindfulness-based behavioral intervention, compared to 18 subjects (6 males) in the waiting list control group (age range 22–29); all subjects (...) experienced mild-to-moderate childhood maltreatment. We analyzed changes in stress, anxiety, depression, mindfulness and self-compassion related to the intervention with linear mixed effects models; we also analyzed the relationships among questionnaire score changes with partial correlation analyses and mediation analysis. Results Linear mixed effects model analyses revealed significant group by time interaction on stress ( p p p p p p r = 0.578, p = 0.001), which negatively correlated with changes in depression ( r = −0.374, p = 0.05) and anxiety ( r = −0.395, p p r = −0.674, p r = −0.580, p r = −0.544, p Conclusion Our results suggest that, to some extent, the mindfulness-based intervention can be helpful for improving self-compassion and psychological health among young adults with a childhood maltreatment history. Clinical Trial Registration www.ClinicalTrials.gov, identifier NCT02447744. (shrink)