In this survey paper it is attempted to present the state of the art in ultrasonic tissue characterization. Analysis of raw radiofrequency data allows for the estimation of acoustic tissue parameters like velocity, attenuation and backscattering. It is argued that prior to analysis and processing of two-dimensional (i.e. B-mode) echographic images corrections for the influences of equipment, sound field and intervening tissue are absolutely necessary. Then promising characteristics of tissue structure can be derived from texture analysis. Postprocessing of echographic images till now did not yield valuable results. Synthetic aperture systems and computerized tomography techniques may bring a break-through.