The excitation functions for the seasonal components (annual and semiannual) of polar motion are calculated based on the atmospheric antisymmetric Rossby-Haurwitz wave (1;-3). The meridional structures of geopotential and horizontal wind of this wave are reasonable approximations of the quasi-standing seasonally varying Rossby waves propagating within the westerly background wind. Both wind and pressure loading contribute to the seasonal components of polar motion. The calculated displacement vector of the annual component agrees well with the observations. The semiannual component, estimated to be smaller by a factor of about ten, is not inconsistent with the data. ¿ American Geophysical Union 1989)