ABSTRACT: Objectives:Individuals with a childhood maltreatment history tend to have various psychological symptoms and impaired social functioning. This study aimed to investigate the related therapeutic effects of a mindfulness-based intervention in this population. Methods:We analyzed self-report questionnaire scores of the Mindful Attention Awareness Scale (MAAS), Non-Attachment Scale (NAS), Adult Rejection Sensitivity Questionnaire (A-RSQ), Interpersonal Reactivity Index (IRI), PTSD CheckList (PCL), and Anxiety Sensitivity Index (ASI), from 16 (3 males) young adults (age range 22-29) with mild to moderate childhood maltreatment, compared to 18 matched participants (6 males) on a waiting list, during both pre- and post-intervention/waiting periods. Analyses were conducted with linear mixed effects models, partial correlation analyses and t-tests. Results:There were group by time interaction effects with the scores of MAAS, NAS, PCL, IRI-Fantasy, and A-RSQ (p < .05). The mindfulness group had significant increase in MAAS (17.325%) and NAS (8.957%) scores, as well as reduction in PCL (15.599%) and A-RSQ (23.189%) scores (p < .05). Changes in non-attachment, but not mindfulness, had significant contributions to the score changes of PCL (16.375%), ASI (36.244%), IRI-Personal Distress (24.141%), IRI-Empathic Concern (16.830%), and A-RSQ (10.826%) (p < .05). The number of intervention sessions attended was correlated with score changes of NAS (r = .955, p < .001), and ASI (r = -.887, p < .001), suggesting a dose-dependent effect. Conclusions:Findings from this pilot study suggest that the mindfulness-based intervention improved mindfulness, non-attachment and empathy, which contributed to reduced interpersonal distress, rejection sensitivity and other psychological symptoms.