In the process of professionalisation of the mediator occupation, it is important to develop the mediator’s competency profile and the profile update mechanisms in view of changes taking place in the social environment. A lack of the competency profile may have a negative effect on the quality of mediation proceedings and on the number of agreements concluded. In this study, in connection with the discussion on the professionalisation of the mediator occupation that has been going on in Poland for many years, the concept and essence of mediator’s competencies, the relevant current legal requirements for mediators as well as selected results of empirical research on the status of the mediator, in particular the mediator’s competencies and their verification, are presented.