The goal of this study was the modelization of the frequency-dependence of the ultrasonic backscatter coefficient in cancellous bone. A twofold theoretical approach was adopted: the analytical theoretical model of Faran for spherical and cylindrical elastic scatterers and the scattering model for a weakly scattering medium, in which the backscatter coefficient is related to the autocorrelation function of the propagating medium. The ultrasonic backscatter coefficient was measured in 19 bone specimens (human calcaneae) in the frequency range 0.4-;1.2 MHz. The autocorrelation function was computed from the 3D micro-architecture measured using synchrotron radiation microtomography. The frequency dependence of the experimental and modeled (autocorrelation) backscatter coefficients were f 3,38±0,31 and f 3,48±0,26 for the experimental and the autocorrelation-based models respectively. The frequency dependence of the theoretical (Faran) backscatter coefficients were f 2,89±0,06 and f 3,91±0,04 respectively, corresponding to Rayleigh scattering (mean trabecular thickness (71 ± 18 μm). These results suggest that the spherical or cylindrical Faran models are not accurate in predicting the backscatter response of trabecular bone and that the modeling by short cylinder or by ellipsoid objects might be more appropriate. On the other hand, a good agreement was found between experimental results for the backscatter coefficients derived using the autocorrelation function. This opens new routes for the investigation of the interaction between ultrasound and bone structure.