Power ultrasound is applied as a mechanical aid to blend and cavitate the medium during the process of salting-out crystallization. Immediately following the addition of the total precipitant needed to the solution. the ultrasound is turned on. The sonoprocess including nucleation and crystal growth is completed in seconds, The experimental results indicate that the variation of ultrasonic energy, duration or mixture volume can he used to yield advantageous control of the mean size and size distribution of resulting crystals. The crystals insonated have perfect shape and show little agglomeration, Since crystallization in such highly supersaturated solution,, is uncontrollable by conventional methods, the insonation plays an irreplaceable role in the process. Based on our experiment, it Should be feasible and valuable to scale up this sonoprocess for industrial application. (C) 2002 Elsevier Science B.V. All rights reserved.