Sterilization of Escherichia coli using high pressure and supercritical carbon dioxide was investigated. The organism was treated at pressures ranging from 5 to 20 MPa and temperatures ranging from 298 to 323 K. Supercritical carbon dioxide was found to be superior for sterilization to liquud and gaseous carbon dioxide. At same temperature, survival ratio was drastically reduced by the elevation of pressure. It was also greatly decreased by increasing temperature. The configurational state of contact between the free surface of the test liquid phase and the dispersal device of supercritical coarbon dioxide had a dominant effect on the decrease of survival ratio. The apparent activition energy of sterilization of E. coli was obtained as 50 kJ . mol(-1).