Distance counselling for clients who have undergone a traumatic experience is one of the hardest tasks for a counselling psychologist. Apart from the chosen counselling strategy, the effectiveness of such work may be influenced by a number of factors, such as the extent of the traumatic experience and the meaning of the traumatic event. A study was undertaken to find out the association of these factors with counselling effectiveness. The aim of the study was to find out the indicators of effectiveness, clarify the limitations and possibilities of phone counselling for people who have suffered psychological trauma, and to develop appropriate recommendations for counsellors. The approaches to diagnosing trauma using test, questionnaires, observation, qualitative and quantitative analyses are discussed. Indicators of change in the psychological state of the client are described, including changes in breathing patterns, speech tempo, awareness, issues and tasks, structure of close future time perspective. Clients’ self-reported data concerning the effectiveness of counselling were also analyzed. The results support the hypotheses concerning the association between self-reported counselling effectiveness and the trauma intensity, the differences in the dynamics of psychological states in clients with different type of traumatic events, and the association between self-reported counselling effectiveness and the type of traumatic event. Recommendations for phone counselling practitioners are proposed.