The inactivation kinetics of food poisoning microorganisms using a combined treatment of carbon dioxide (CO 2 ) with high hydrostatic pressure (HHP) was investigated. Staphylococcus aureus, Fusarium oxysporum, and Fusarium sporotrichioides were totally inactivated by a combined treatment of carbonation and HHP at 500 MPa. Bacillus subtilis, a spore forming bacteria, were not completely inactivated after the combined treatment. The microorganisms treated by carbonation and HHP were exponentially reduced in a pressure range and the D p -value, the Z p -value, and the activation volume were determined. UV absorbing materials leaked from injured cells. Morphological changes of the cells were observed by scanning and transmission electron microscopy.