The result of a B-scan ultrasound examination is strongly dependent on the type of the used B-system, the chosen system parameters and the experience and critical analysis of the clinical investigator. The estimation of quantitative acoustic parameters, independent of the type of the used B-system, is one way to overcome the subjective nature and the problems of the interpretation of B-scan images. A procedure was developed to determine acoustical tissue specific parameters (ultrasound attenuation, relative backscatter coefficient) in terms of the ultrasound spectroscopy and to correct the system effects. A requirement for the calculation of acoustical parameters is the availability of primary rf echo signals without any preprocessing. Up to now measurements of phantom materials and in-vivo investigations on human testis and prostate have been carried out. The effects of pathological changes in the tissue state on the acoustical parameters are demonstrated in some examples.