Two years of TOPEX/POSEIDON altimeter data have successfully been used to study the mesoscale field in the Mediterranean and to investigate the seasonal and year-to-year variability of the sea level and eddy statistics in this basin. The mesoscale field described by TOPEX/POSEIDON revealed a strong, but subbasin dependent, seasonal signal. Year-to-year variations are also evident in terms of both intensity and position of the main mesoscale features. Crossover analysis indicated the existence of a meridional transport of eddy momentum away from the Algerian current due to the northward migration of mesoscale eddies. A comparison between mesoscale features detected by the altimeter and contemporaneous features observed using advanced very high resolution radiometer (AVHRR) sea surface temperature has been made for the following Mediterranean subbasins: the Algerian basin, the Levantine basin, and the Tyrrhenian Sea. The results definitively prove the direct relation between sea level anomalies and the Mediterranean eddy field. ¿ 1998 American Geophysical Union