In 1980-81, 1983-84, and 1985-86 airborne surveys with the electromagnetic reflection (EMR) system were made of Ekström Ice Shelf, Antarctica. The EMR data were supplemented by measurements of surface elevation with radar altimetry during flights at a constant pressure altitude. The accuracy measurements of ice thickness in areas with clearly developed bottom reflectors was used to generate a plot of surface elevation against ice thickness. The effect of changing barometric pressure during flights could be reduced by this means. Elevations were calibrated over the open sea at the beginning and end of each flight. On the basis of these data, the surface elevation, ice thickness and isostatic anomalies have been mapped over the ice shelf.