The impact of a chemically and texturally equilibrated melt phase on the shear creep and attenuation behaviors of polycrystalline olivine has been measured experimentally at seismic-to-subseismic frequencies. The experiments were performed on aggregates that had a particularly uniform and fine grain size (~3 &mgr;m). The effect of the melt phase (~5 vol%) is to decrease the (Newtonian) viscosity by a factor of ~6; there is no dramatic disaggregation effect or melt-induced plummeting of the shear modulus. Both the melt-free and melt-bearing aggregates display an attenuation band of the form QG-1∝f-0.4. This response cannot be attributed to a variation in microstructure; it is intrinsic to the diffusional creep behavior. There is no unique effect of the melt phase on the attenuation response: the slight increase in absorption of partial melt specimens is explained fully by the effect of the texturally equilibrated melt on aggregate viscosity. ¿ 2000 American Geophysical Union