The SEASAT altimeter derived wave height ('on-board' estimate) has been successfully compared with ship reports over the North Atlantic Ocean, for 163 passes of SEASAT, from September 15 to October 9, 1978. Satellite wave height measurements reveal features of great interest: first, SEASAT data are used to evaluate the spectral wave forecasting model, DSA 5, of the French Meteorological Office (La M¿t¿orologie Nationale). Then, the analysis of 26 SEASAT passes through low-pressure areas shows the geographic distribution of strong sea states in storms and the large variations of wave height over short distances, an important observation for wave modeling and ship routing.