A sediment wave field in the western Gulf of Mexico is similar to many other fields that are located on continental rises and related to thermohaline contour currents, especially western boundary undercurrents. Such currents should not occur in the Gulf, because it is silled. At present, the only postulated source of deep currents in the Gulf is the Loop Current (in the eastern half), eddies detached from it, and Rossby waves but no thermohaline currents. If any of the postulated processes cause the mud waves, it is a new mode of formation. If they do not, much more needs to be learned about deep Gulf circulation. These questions are important, because the sediment waves represent paleoceanographic conditions that have persisted for over 5 million years. ¿ American Geophysical Union 1994