BACKGROUND: Mindfulness improves mental health and clinical conditions including psychosis and modulates attentional processes including salience-the automatic direction of attention to prominent elements. Aberrant salience-the exaggerated significance attribution to perceived elements-is associated with psychotic experiences, but its interactions with mindfulness remain unexplored. METHODS: This pre-post-intervention pilot study included 21 participants completing an 8-week Mindfulness-Based Health Promotion (MBHP) course with measurements before (T0), after (T1), and three months post-course (T2). Primary outcomes were mindful attention (Mindful Attention Awareness Scale, MAAS), decentering (Experiences Questionnaire, EQ), aberrant salience (Aberrant Salience Inventory, ASI), and correlations between time-dependent changes (T1-T0, T2-T0, T2-T1). Secondary outcomes included qualitative reports on Motivations, Learnings, Preferred Practices, and Stress Management. RESULTS: Regarding mindfulness, MAAS and EQ continuingly increased (T0 vs. T1/T2). Regarding aberrant salience, the factor Heightened Cognition (ASI) increased post-course (T0 vs. T1), whereas Heightened Emotionality (T0 vs. T2) and Total Aberrant Salience (T1 vs. T2) decreased. Importantly, MAAS (T1-T0, T2-T0) correlated negatively with Heightened Emotionality (T2-T0). Qualitative findings revealed consistent stressors but improved stress management, integrated mindfulness practices into participants' daily lives, and potential mechanisms of presence, observation, perspective change, and emotion regulation underlying decreased aberrant salience. CONCLUSION: Mindfulness may modulate pre-attentional and attentional processes and improve well-being and stress management, as reflected by reduced aberrant salience and promoted mindful attention and decentering. Our findings suggest that mindful attention may play a crucial role in reducing aberrant salience, offering a promising direction for future research on mindfulness interventions in psychosis.