In the course of the last 50 years, ultrasonic atomisation has developed from a somewhat exotic laboratory technique with few, hardly used applications to a well established one with a broad spectrum of applications. Today＇s optimised atomisers for process engineering applications operate at volume flows between a few ml/min and several 100 l/h and droplet diameters between 1 and about 150 micrometers. The technique can handle both "normal" liquids for therapeutic inhalation, for air humidifiers, carburettors, oil burners, etc. as well as solutions and suspensions for spray drying and melts of low to high melting temperatures and viscosities. The author reports on the development of ultrasonic atomisers and not only describes the physical principles and technical features of the various atomiser types but also considers borderline topics of droplet and particle generation with vibrating nozzles and cavitation chambers.