Damping of acoustic gravity waves due to the ionization of the ionosphere is studied, and damping rates are calculated under the assumption that the wave vector is real. The magnitude of the damping rates is estimated under ionospheric conditions. The present paper is in fact a generalization of the paper by Miesen et al. (1989), where the geomagnetic field was assumed to be parallel to the surface of the Earth. An error in this paper is corrected. ¿ American Geophysical Union 1991