Wind-wave flumes have been added to the laboratory facilities since a long time, in order to simulate natural wind lv-aves. Most wind-wave flui'nes have been equipped in addition with mechanical (regular) wave generators to avoid extreme small model scales. For some time past a programmed (irregular) wave generator has been installed in one of the existing wind flumes of the Delft Hydraulics Laboratory. After a historical review of the development of wave generating facilities a comparison has been made of the various kinds of wave generation. Moreover, some records of North Sea wave conditions have been added to the comparison.