The diploma thesis deals with the issue of assessing the risks of major industrial accidents of a selected company. Its aim was to identify and determine the probability of failures leading to a major industrial accident and its possible effects on the basis of an analysis of a major industrial accident, which occurred in 1995 in the company Chemko Strážske, state enterprise. The theoretical part of the diploma thesis provides an overview of selected major industrial accidents in the world and in the Slovak Republic, which created the initial conditions for the creation of basic requirements for the prevention of major industrial accidents. A part of the diploma thesis is the theory of risk management from the industrial safety point of view, as well as current approaches to assessing the risks of major industrial accidents. These define current risk analyzes and software tools designed to model the impacts of major industrial accidents in combination with the use of quantitative risk assessment standards. For the analysis of a major industrial accident in the company Chemko Strážske, state enterprise, we applied deductive fault tree analysis and event tree analysis to determine impacts. The result of the solution is the assessment of elementary failures and failures leading to a major industrial accident in the company Chemko Strážske, state enterprise, and determination of possible impacts, which can be subsequently modeled in software programs ALOHA, ADAM, TerEx.