The thermoresistance of spores of Clostridium difficile strains belonging to the different toxigenicity groups was compared in the study. Among spores of toxigenicity C. difficile strains (26 C. difficile strains produced toxins A and B (TcdA+TcdB+) and 32 C. difficile strains produced only toxin B (TcdA-TcdB+) were high thermoresistant. Between spores of non-toxigenic C. difficile strains much lower thermoresistance was observed. In conclusion, more studies are needed to clarify the importance of spores transmission in the increasing number of AAD cases in Poland.