Background: One of the tasks of a level I trauma center is quality improvement of level II and level III regional hospitals and emergency medical services by means of continuous education and learning processes. One of the tools for this, which provides constant monitoring of the quality of treatment, is feedback. The purpose of the study was to evaluate the effect of feedback on the quality of trauma care. Methods: Retrospective cohort study comprising two periods of time, 2012–2013 and 2017–2018. The study group included physicians and pre-hospital staff who treated patients prior to referral to the level I center. Upon arrival when the trauma teams identified issues requiring improvement, they were asked to fill in feedback forms. Data on patients treated in the trauma shock room for whom feedback forms were filled out were also extracted. Results: A total of 662 feedback forms were completed, showing a significant improvement (p ˂ 0.0001). The majority of the medical personnel who received the most negative feedback were the pre-hospital staff. A significant increase was revealed in the number of feedbacks with reference to mismanagement of backboard spinal fixation, of the pre-hospital staff, in 2012–2013 compared to 2017–2018 (p < 0.001). Improvement in reducing the time of treatment in the field was also revealed, from 15.2 ± 8.3 min in 2012–2013 to 13.4 ± 7.9 min in 2017–2018. Conclusion: The findings show that feedback improves the treatment of injured patients. Furthermore, constantly monitoring the quality of treatment provided by the trauma team is vital for improvement.