Analysis of the salinity distribution along three quasi-meridional hydrographic sections in the eastern North Atlantic shows that different mesoscale processes act to mix the Mediterranean Water with the adjacent water masses. In the region of transition with the Antarctic Intermediate Water in the south, the salt transport by the meddies seems to account for most of the observed lateral diffusive exchanges at the large scale. In the north these exchanges are contributed to by parcels of both Mediterranean Water and Subarctic Intermediate Water travelling on average in opposite directions. Also in the north but at a deeper level, transition with the Labrador Sea Water is characterized by a pronounced thermohaline front. Coherent mesoscale structures carrying deep Mediterranean Water escape northward from that front. A simplified unidirectional mixing model is used diagnostically to relate the basic parameters associated with the mesoscale structures to those characterizing lateral mixing at the large scale.