International Framework Classification of Resources/Reserves of Solid Fuels and Mineral Commodities (UNFCR) is the best one for deposit feasibility evaluation. Within it the reserves are the main concern. They are defined as extractable ammount of mineral commodity in given econome conditions, considering mining losses and dilution. UNFCR in general is not contradictory to polish classification and can be casily applied. The only, but substantial difference is the mode of defining reserves. In Poland they are ammount of mineral commodity within the deposit ("in place"), designed for mining in the existing feasibility study. They are rather the "reserve base" for reserve calculations as defined in UNFCR. The extractable reserves are named in Poland "operational" and they should be considered in official resources/reserves classification. Because of different meaning of term "reserves", it should be clearly stated in the UNFCR, if it is used for ammount in place or extracable.