Measurements of the ultrasound attenuation were carried out in 10 normal testes and 20 pathologically changed testicular tissue biopsies in vitro after formalin fixation. The ultrasound attenuation as function of the frequency was recorded ultrasound-spectroscopically about the complete frequency spectrum of the ultrasound-broad range transformer (3-8 MHz). The frequency dependence of the attenuation behaviour differed in the 10 normal testes from the 20 pathologically changed biopsies by smaller values of the ultrasound attenuation coefficient a (linear regression analysis). The ultrasound attenuation in a characteristic measuring point allows the differentiation between normal and pathologically changed testicular tissue. The following comparison with the histologic evidences showed the correspondence of the results.