We report here on the observation of a geomagnetic signature in the zonal eastward plasma flow, which is a striking feature of the equatorial ionosphere in the evening quadrant. These observations were derived from (E¿B)B2 measurements made with the cylindrical double floating probe experiment carried on the Dynamics Explorer 2 (DE 2) satellite. The signiture consists of a crest-trough-crest effect in the latitude dependence of the eastward plasma flow with the crests at ¿8¿ dip latitude and the trough nearly centered at the dip equator at all geographic longitudes. This phenomenon can be readily interpreted in terms of the altitude dependence of the F region dynamo electric field, and it is related to dip equator signatures in the plasma density and the magnetic declination which have been reported earlier.