Satellite radar altimetry can be used to infer the thickness of floating ice shelves around Antarctica under the assumption of hydrostatic equilibrium. Ice shelf thickness is an essential parameter in mass budget calculations and is one of the more poorly characterised. Using data from the ERS-1 radar altimeter recorded in 1994–5, we calculate the thickness of Larsen C ice shelf on the Antarctic Peninsula. The surface elevation was determined to an accuracy of -2.3 ± 4.35 m as compared to elevations from the laser altimeter onboard ICESat. Using a model for firn depth and density, we created a 1 km grid of ice shelf thickness for Larsen C. The accuracy of the ice thickness e retrieval was determined from independent airborne radio echo sounding data. The results indicated a bias of -0.22 m and random error of 36.7 m, which is equivalent to 12.7% of the mean thickness for this ice shelf.