The presented paper focuses on the resolution of collective disputes, i.e. conflicts between trade unions and employers. A collective dispute is the main form of institutionalisation of a conflict between an employer and employees in the Polish legislation. The act regulating this type of conflict was introduced in the period of system transformation in 1991. It allows for control over the course of industrial conflicts, setting a procedure to resolve them, where an integral part is mediation between the parties to the dispute. This paper consists of two parts. The first one is devoted to the place of the collective dispute and mediation in the system of industrial relations. The second part presents an empirical study based on a case study analysis, which was used to present an analysis of mediation in a collective dispute in an enterprise.