We examine the angular distribution of auroral kilometric radiation (AKR) based on a 38-month data set of GEOTAIL plasma wave observations. We show that the AKR illumination pattern becomes narrower with increasing frequency above 300 kHz. The difference is more evident in the duskside zone and when geomagnetic conditions become more disturbed. We also show that AKR is more active on the winter hemisphere especially for the higher frequency range.¿ 1997 American Geophysical Union