The permittivity of a rice (Oryza sativa L. japonica)-cell suspension was measured in the frequency range from 0.2 to 20 MHz. A good linear correlation (=r) of 0.999 was observed between the permittivity at 0.41 MHz and the cell density. Permittivity was lost as a result of cell destruction by aging, ultrasonication, or boiling. From a comparison between changes in the permittivity of the cell suspension and freezing curves obtained by differential scanning calorimetry, the major freezing injury was believed to be due to damage to the plasma membrane. Freezing damage was measured by the intact cell ratio calculated from the permittivity and 2,3,5-triphenyltetrazolium chloride (TTC) reduction viability assay under various freezing conditions. The effects of changes in the concentration of dimethylsulfoxide used as a cryoprotectant and in the cooling rate showed similar trends for the intact cell ratio and TTC viability, although there was a quantitative discrepancy between them.