The objective of the research study was to assess the effect of microwave irradiation on the selected properties of potato maltodextrins showing different depolymerization degrees. The research material consisted of commercial maltodextrins of three saccharification degrees and one hydrolysate of a medium hydrolysis degree produced in a laboratory. All the maltodextrins were irradiated using a 440 W or 800 W microwave field. While carrying out the research, the effect was analyzed of microwave irradiation on the value of glucose equivalent ‘DE’, as well as on the mean molecular mass of branched and non-branched fractions with long side chains and of the branched short chains. This effect was studied using a Gel Permeation Chromatography (GPC). Also, the change in the carbohydrate composition of starch hydrolysates was studied using a High Pressure Liquid Chromatography (HPLC). Furthermore, the impact of microwave field interaction on the number of free radicals generated in starch hydrolysates was studied using an Electron Paramagnetic Resonance (EPR). Based on the analyses accomplished, it was found that the microwave irradiation had a significant impact on the change in the properties of maltodextrins. All the maltodextrins investigated, modified in the microwave field, had a lower content of branched fractions with short side chains. On the other hand, the degree of retro-gradation depended both on the saccharification degree of starch and the power of microwaves used to modify hydrolysates. The accomplished research of the starch hydrolysates using the Electron Paramagnetic Resonance proved that free radicals were present in all the maltodextrines investigated.