There are several criteria for determining mineable oil shale reserves and resources. Three characteristics: thickness, average calorific value, and depth of the mineable bed were used in the era of planned economies, based on available mining technology capabilities. The reserve cut-off values had been estimated mostly for the needs of the large power industry. A research project to find new characteristics for the determination of oil shale reserves which are compatible with today＇s economy was performed in 1996/1997. According to this study, a given oil shale bed is defined as a reserve, provided that the costs of ifs mining and delivery to the consumer are lower than the consumer＇s expenditure of coal procurement. This study also defines an oil shale bed with an energy rating above 25 GJ/m(2) as a resource. Using these criteria, Estonia＇s oil shale resources are over 6 billion tonnes, or over 47 EJ (EJ -10(18) J) of energy, including active reserves exceeding 2 billion tonnes, with over 17 EJ of energy.