A model is presented to describe the attenuation of seismic waves in a partially saturated rock. In particular, we include the dissipation due to contact line movement. In some cases this can dominate the dissipation mechanisms. The model includes both dissipation due to viscosity and contact line movement. This additional dissipation can increase the specific dissipation function by an order of magnitude. This could account for some of the observed difference between theory and experiment. An exact calculation of the dissipation due to contact line movement in an inviscid fluid is also presented. ¿ American Geophysical Union 1988