The paper compiles the results of laboratory tests conducted to highlight the various aspects related to CO2 sequestration in coal seams. It is therefore worthwhile to gather the information available on the interactions of CO2 with coals and the effects of CO2 on coals' properties in order to attempt a prediction of the long-term effects of sequestration. Underground storage of CO2 allows for emission reduction, awaiting the development of other sources of energy. CO2 can be stored in deep and permeable rocks isolated by overlying impermeable rock strata. In order to predict the CO2 storage capacity of a candidate coal seam and to model its long-term stability, physical properties of the coals must be known accurately. Thus, the sorption isotherms of CO2 on coal need to be treated carefully in order to obtain the desired information. The experiments were run on a low-rank coal samples (VM 33.4%) in the form of plates 15 x 15 x 5 mm. The experiments were conducted following the standard volumetric method at the temperature 298K, using the volumetric method. Tested sorbates were pure gases: CO2 and CH4 and their mixtures in variable proportions. The considered pressure range was 0-4MPa. Sorption data and chromatographic analyses of gas mixture released during desorption reveal a clear dependence between the actual proportions of the mixture in the ampoule and the composition of desorbed gas. Low concentration of CO2 in the initial mixture causes the desorbed gas mixture to be enriched in CH4, evidencing a preferential sorption of CO2. The factor controlling the selective sorption of gases is the microstructure of coal types in the sample, as they display various porosity and swelling rate due to the presence of gases in the porous structure. Strong and specific interactions were observed between the sorbate and pores as well as stresses due to the swelling of the coal matrix, so their influence on the gas transport processes must be accounted for whilst modelling the gas storage and methane recovery operations.