PCT No. PCT/EP95/03476 Sec. 371 Date Feb. 28, 1997 Sec. 102(e) Date Feb. 28, 1997 PCT Filed Sep. 4, 1995 PCT Pub. No. WO96/07460 PCT Pub. Date Mar. 14, 1996In a method for the desalination of seawater, there is evaporated and condensed the seawater, within a primary system, and a secondary medium, preferentially untreated water, within a compressor-containing, self-contained secondary system spatially separated from the primary system. The seawater is evaporated by heating in the presence of the secondary medium previously heated in the compressor at excess pressure, the latter medium is evaporated in the secondary system through condensation of the seawater vapour and the seawater vapour is led through a cyclone separator. The total seawater flow supplied to the primary system is subdivided into a first component flow and a second component flow of at least approximately equal magnitude, the first component flow, in a first heat transfer unit through which flows the hot water distillate at the output of the primary system, and the second component flow, in a second heat transfer unit through which flows the discharged hot wash-out, being brought to a temperature approaching the boiling temperature in the primary system. A value between greater than 1 and less than 2 is chosen for the ratio of supplied total seawater quantity per unit of time to wash-out quantity per unit of time (concentration factor CF). A method of this kind is suitable for thermal seawater desalination, enabling the production of germ-free water distillate of high quality under simultaneously lesser concentration of the seawater being evaporated and nonetheless saving energy.