Quality estimation of a brecciated dolostone (triassic-jurassicof the subbetic zone) is realised by using the ultrasonic technique. For this purpose, the relationship between ultrasonic parameters, compressive strength and petrographic characteristics is assessed. The ultrasonic parameters used in this study are: compressional and shear wave velocities, and their ratio; the signal attenuation and, the energy of the signal. Our study shows that the energy of the signal is the most appropriated parameter for predicting the quality of the brecciated dolostone. Thus, high values of energy of the signal imply a greater rock strength and, consequently, a better rock quality