From July 1980 to February 1981, ten current meters on three moorings were deployed in the 200- to 700-m-depth range over the continental slope in the northwestern Gulf of Mexico. The currents were characterized by energetic fluctuations with time scales of a week to several months. Westward drifting Loop Current anticyclones provided the principal driving mechanism for the fluctuations. Longshore current speeds at the 200-m depth occasionally exceeded 70 cm/s and were persistently >50 cm/s during a 2-month period in the fall. Except during a hurricane, the currents were only marginally coupled with the winds measured at Brownsville, Texas. Tidal motions accounted for <1% of the current variance.