Analysis of receiver functions from an eight-station network on the Saudi Arabian shield indicates that the Moho depths vary between 35--38 km. The crust appears to be rather felsic in nature as evidenced by Poisson's ratios of 0.25--0.27. A prominent negative phase following the Moho conversion is suggestive of a zone of velocity inversion. Indication of mantle stratification is observed beneath the coastal region of Arabia, by way of an additional upper mantle discontinuity at about 240 km. The conversions from the 410 and 660-km discontinuities are significantly delayed, suggesting a slow and hot upper mantle.