Fundamental mode Rayleigh wave phase velocities have been obtained for the Albuquerque-Belen basin of the Rio Grande rift. Source and instrumental characteristics limited useful data to the period band 6-12 s. Inversion of the phase velocity data yielded a model for the shear velocity of the upper 20 km of the basin. The model contains two velocity inversions, one near a depth of 6 km, the other near 18 km. The velocity inversion near 18 km is attributed to the effects of a midcrustal magma body known from previous studies; the cause of the low-velocity zone near 6 km is not known, but it may be caused by an upper crustal magma body. The average of the velocities for the upper crustal model presented here (Bave ≈ 3.33 km/s) is comparable to those reported in previous studies.