The effect of calcium compounds present in lignite on the effectiveness of steam gasification of lignite chars has been studied at the temperature of 750° C. lignites from three Polish mines were used. Samples were demineralized with 2M HCl to remove alkali and alkaline earth metals. The demineralized lignites were loaded with Ca using: calcium acetate Ca(CH3COO)2, calcium hydroxite Ca(OH)2 and calcium carbonate CaCO3. The lignite samples were carbonized at the temperature of 900 °C in order to obtain lignite chars. The gasification process, applying steam as the oxidizing agent, was studied using thermogravimetric analysis at the temperature of 750 °C. For the process of gasification, the catalytic effect caused by the presence of calcium in lignite was found to be very important (2-7 times reaction rate acceleration). Even more important appeared to be the fact, that the effect of calcium was practically independent of the kind of calcium compound used. The inherent minerals present in raw lignite exert a similar catalytic effect to that caused by the added calcium.