AbstractObjectivesMindfulness may be a helpful tool to enhance psychotherapists' self‐care and intrapersonal skills. To gain deeper knowledge about how to improve mindfulness skills in child and adolescent psychotherapists, we investigated the impact of two mindfulness‐based workshops and a self‐experience interval (individual homework practice of mindfulness exercises) on quantitative and qualitative measures in a nonrandomised study.MethodsThirty‐six trainee psychotherapists took part in the 6‐week workshop‐based mindfulness intervention (experimental group, EG). Twenty‐one trainee psychotherapists served as a comparison group (CG). All participants completed the Kentucky Inventory of Mindfulness Skills (KIMS‐D), the Self‐Compassion Scale (SCS‐D) and the Empathy Scale for Social Workers (ESSW) at pre, post and 6‐month follow‐up. Benefits of the regular use of mindfulness practice of 10 trainee psychotherapists in the EG were analysed using qualitative content analysis at the 6‐month follow‐up.ResultsThe quantitative analyses revealed a significant increase over time on the KIMS‐D subscale “acting with awareness” in both groups and a significant increase over time on the KIMS‐D subscale “accepting without judgment” in the EG in contrast to the CG. The qualitative analyses indicated good acceptance of the mindfulness‐based workshop intervention. Qualitative changes referred to the achievement of knowledge in theory and practice concerning mindfulness and the integration of mindfulness‐based interventions in everyday life.ConclusionThe mindfulness intervention appeared to produce quantitative long‐term changes concerning mindfulness aspects and qualitative changes. Future research should elaborate conditions (i.e., intervention length, intensity and setting) that may influence the manifestation of quantitative and/or qualitative changes in mindfulness‐based workshop interventions in professionals.