The porosity dependence of ultrasonic velocity in porous sintered materials has been modelled using the self-consistent spheroidal inclusion theory. Considering the pores to be oblate spheroids, an effective aspect ratio has been determined from experimental data, which serves as an additional parameter to describe the observed variation in ultrasonic velocity with porosity. With the exception of two cases in the ten investigated, this single parameter describes satisfactorily the variation of both longitudinal ultrasonic velocity and transverse ultrasonic velocity with volume fraction of pores.