The introductory part of the diploma work is focused on imperfect competition, its causes, forms of imperfect competition and then the oligopoly, which is a form of imperfect competition. Oligopoly is a market structure in which are companies aware of interdependence. The second part of the diploma work consists of an analysis of the structure of the market with wood biomass in the Slovak Republic. This part deals with the production of wood biomass, its import, export by Slovak companies that process wood biomass and primary research. Primary research was conducted via an online questionnaire and was focused on the volume of raw material, method of delivery, the customer structure and question of the biggest problem in business with wood biomass. The last part of the diploma work includes an evaluation of the results and proposals of the appropriate solutions to improve the current state of wood biomass in the Slovak Republic.