The purpose of this study was to characterize renal cell carcinoma tissue by the measurement of microacoustic properties. A scanning acoustic microscope system operating in the frequency range of 100-200 MHz was employed and the attenuation constant and sound speed were measured on the two-dimensional distribution. The values of attenuation constant and sound speed were lower in both kinds of cancer cells than those in normal kidney, although a significant difference was not found between the clear cell and granular cell. Also, both acoustic parameters of cancer cells were significantly lower than those in hemorrhage and fibrosis. These data suggest that the elasticity of renal cell carcinoma tissue may be lower than that of normal kidney. Moreover, the high intensity echo in clinical echography may be related to the heterogeneity of the microacoustic field in the carcinoma tissue.