ENBackground: Further developments in trauma care training for mental health staff are needed to ensure that trauma survivors are recognised and get the most effective care. The evaluation of the effects of trauma care training programs would enable the untangling of the most efficient ways of building the competence of clinicians who encounter trauma-exposed patients in their routine clinical practice. Objective: We aimed to analyse longitudinal changes in mental health professionals’ perceived trauma care competencies after a brief online trauma care training, and to examine associations between these changes and specific work-related characteristics. Method: In total, 223 mental health professionals, 96.4% women, 42 years on average, and 51.6% with more than 10 years of clinical practice, participated in a brief online trauma care training programme. The Readiness to Work with Trauma-Exposed Patients Scale (RTEPS) was used to measure perceived trauma care competencies at the pre-training, post-training, and at a 3-month follow-up. Results: Training had a significant effect on all measured perceived trauma care competencies of assessment, treatment and affect tolerance at post-training and 3-month follow-up. We also found that many years of unspecific clinical practice did not contribute to perceived trauma care competencies, and the training was perceived equally beneficial by professionals with more or less clinical practice. Conclusions: Our study indicates that brief training can have lasting effects on clinicians’ self confidence in trauma care. Further investigation of factors associated with the effects of training might help to increase the effectiveness of the training programs. Keywords: trauma care; competence; training; PTSD; healthcare. [From the publication]