A thin jet of liquid issuing from a nozzle at a high velocity disintegrates spontaneously into droplets under the action of surface tension. A periodic disturbance of the jet can be used to control the disintegration so as to make all droplets of the same size. A system for generating monodisperse sprays according to the principle outlined above has been designed and built. The jet is modulated by axial vibration of the nozzle, which is mounted at the center of a membrane. The membrane is vibrated by means of electrostrictive elements. Droplets in the diameter range 40–15 &mgr; have been produced at a vibration frequency of 20–300 kHz. The stream of droplets has been analyzed in several ways. A jet of air perpendicular to the droplet stream has proved to be of special value. Several air jets, pulsed in suitable phase relations, are utilized to disperse the stream of droplets and to prevent the droplets from coalescing during the drying phase of the aerosol generation.