The purpose of this work is study of mediation as a new methodological approach to interaction with audience of art museum. The first chapter is devoted to complex analysis of the spectrum of socio-cultural conditions that led to a change of visitor’s role in the museum communication and an emergence of a new vision of museum’s mission. A general characteristic is given of a new approach that focuses on the audience as a center of museum's activities and thus makes a search of new methods of interaction with the public a problem of current interest. The second chapter explores the concept of "cultural mediation": different connotations of the term are given and inconsistencies in its use are removed; an author’s definition of the concept is offered. In the third chapter key characteristics of mediation as a specific method of interaction with the public are analyzed, and this method is compared to the traditional forms of gallery education (guided tours, lessons). The task of applied research is to develop a curriculum of training of mediators for the 3rd Ural Industrial Biennale of Contemporary Art. The list of professional competences and goals of training for a mediator is formed based on the analysis of the experience of mediators at the Manifesta 10 Biennial and the study of the professional documents of the European associations of mediators. Additionally, the main principle of studying and representing works of art is explained, which is the basis of mediators training.