Background/Aim. Traumatic stress refers to physical and emotional reactions caused by events which represent a life threat or a disturbance of physical and phychological integrity of a child, as well as their parents or gaerdians. Car accidents are the main cause of posttraumatic stress disorder (PTSD) in children. The aim of this study was to preview clinical efficiency of systemic family therapy (SFT) as therapy intervention in treatment of children with posttraumatic stress disorder (PTSD) traumatized in car accident under identical circumstances of exposure. We pointed out the importance of specific family factors (family cohesion and adaptability, emotional reaction of the parents) on PTSD clinical outcome. Methods. The sample of this clinical observational study included 7-sixth grade pupiles - 5 boys and 2 girls, aged 13. All of the pupils were involved in car accident with one death. Two groups were formed - one group included three children who were involved in 8 SFT sessions together with their families. The second group included 4 children who received an antidepressant sertraline in the period of three months. Results. Two months after the car accident, before the beginning of the therapy, all of the children were the members of rigidly enmeshed family systems, considering the high average cohesion scores and the low average adaptability scores on the FACES III. Three months after the received therapy, having evaluated the results of the therapeutic approaches, we established that the adaptability scores of the families included in the SFT were higher than the scores of the families of the children who received pharmacotherapy with one boy still meeting the criteria for PTSD. Conclusion. Systemic family therapy was efficient in the treatment of children with PTSD, traumatized in car accident. Therapy efficiency was higher when both parents and children were included in SFT than in the case when they were not included in the family therapy. The change in the functioning of the family systems was not accidental or simply time-dependant, but it depended on the therapy which was applied and the increased level of family adaptability as the main risk factor of retraumatization.