Range estimates from a radar altimeter have biases which are a function of the significant wave height (SWH) and the satellite altitude angle. Based on results of pre-launch Geosat modeling and simulation by the Johns Hopkins Applied Physics Laboratory, a correction for SWH and attitude was already applied to the sea surface height estimates from Geosat's production data processing. By fitting a detailed model radar return waveform to Geosat waveform sampler data, we can provide an independent estimate of the height bias due to SWH and attitude angle. The waveform fitting also produces independent estimates of the SWH and of the attitude angle. The waveform fitting has been carried out for 10-s averages of Geosat waveform sampler data over a wide range of SWH and attitude values. Our results confirm that Geosat sea surface height correction is good to well within the original decimeter-level specification but that an additional height correction can be made at the several centimeter level. Our results are expressed as additive corrections to the NOAA-distributed Geosat estimates of sea surface height, SWH, and attitude, and we provide coefficients for the polynomial expressions for these corrections. ¿ American Geophysical Union 1990