Strong evidence is presented for the existence of barotropic shelf waves at diurnal frequencies in the shelf-break region of the southern Weddell Sea. Rotary spectra from long-term current meter records on the slope, at the shelf break and on the shelf show the same rotational sense as that predicted by a barotropic model. Phase speeds of the zero-mode shelf waves calculated from tidal analysis and rotary coherencies of current meter pairs oriented in an along-shelf direction are in the same range as that predicted by barotropic theory except for the O1 constituents. The weak stratisfication of the Weddell Sea in the region of the slope results in nearly barotropic motion at diurnal frequencies. The anomalous behavior of the O1 constituent could not be explained. Abstract Strong evidence is presented for the existence of barotropic shelf waves at diurnal frequencies in the shelf-break region of the southern Weddell Sea. Rotary spectra from long-term current meter records on the slope, at the shelf break and on the shelf show the same rotational sense as that predicted by a barotropic model. Phase speeds of the zero-mode shelf waves calculated from tidal analysis and rotary coherencies of current meter pairs oriented in an along-shelf direction are in the same range as that predicted by barotropic theory except for the O1 constituents. The weak stratisfication of the Weddell Sea in the region of the slope results in nearly barotropic motion at diurnal frequencies. The anomalous behavior of the O1 constituent could not be explained.