The circulation of the intermediate and deep waters of the Tyrrhenian are discussed in the light of recent observations in the Southern Tyrrhenian from current meters, submerged floats, and hydrographic data. The observed flow in the Sardinian Channel suggests that the deep circulation below the intermediate water level is such as to import Western Mediterranean deep water and export a mixed product (with the intermediate water) of sufficient magnitude (6 700 km super(3)/yr) to be of significance in the thermohaline circulation of the Western Mediterranean. The Levantine intermediate water layer is divergent: sustaining, in addition to this downwelling, an upward flux to the surface layer, and the horizontal fluxes north through the strait of Corsica and south through the Sardinian Channel. To support this divergence approximately 40 000 km super(3)/yr, or most of the Levantine intermediate water passing through the strait of Sicily, must enter directly into the Tyrrhenian around the eastern tip of Sicily. Evaporation and the upwelling of intermediate water play approximately equivalent roles in salting the surface waters. Winter convective mixing appears to be the primary mechanism for the upward loss of intermediate-layer salt.