The SEASAT satellite, launched on June 27, 1978, carried a radar altimeter designed to measure the altitude of the satellite above the ocean surface, the surface wave height, and the ocean-surface backscatter coefficient from which wind speed can be inferred. Postlaunch engineering assessment indicated that the SEASAT altimeter met the performance specification for 10-cm precision (noise) in the altitude measurements. However, to determine the accuracy of this measurement as well as the accuracy of the wave height and wind speed measurements a significant calibration, validation, and model development effort was required. This summary describes the instrument, atmospheric, and geophysical effects which influence the radar altimeter measurement accuracies and the attendant correction models adopted for the altimeter geophysical data record. Also summarized are the activities of the SEASAT Altimeter/Precision Orbit Determination Experiment Team directed towards the validation and improvement of these models, as well as the investigations required to assess the accuracy assessment is made for the various altimeter measurement corrections which are included on the altimeter geophysical data record.