The phenomenon of rocbursts has accompanied mining in the Czech part of the Upper Silesian Coal Basin (USCB), just as it has in the Polish part, since the beginning of the last century, and its consequences remain pertinent today in the Karviná part of the Ostrava-Karviná Revir (conventional term for Czech part of the USCB, hereinafter referred to as OKR), where the basal seams of the Karviná Formation are extracted. Rockbursts are one of the most serious hazards in mining. They arise as a result of releasing stress in the rock mass in excess of its ultimate tensile strength. Demonstrable causes are both specific geological characteristics of the rock mass and mining activity that disrupts the primary stress condition. In the Czech part of the USCB, there are records of rockbursts dating back to as early as last century. Since then, 450 such cases of rockbursts of varying intensity have been recorded. Many experts have studied rockbursts and their causes since the time of their first occurence early last century. Neverheless, a number of aspects, especially the impact of geological characteristics, on the risk of rockbursts have not yet been fully explained. Opinions on the effects of various geological factors and their significance for the risk of rockbursts have evolved with the development of knowledge of their natural relations and using experience gained from mining operations.