Abstract: The special chemical and physical environment arising from acoustic cavitation can provide a unique means for the preparation of novel materials with unusual properties. Recently, sonochemical processing has proved to be a useful technique for generating nanomaterials. We review the main types of ultrasonic preparation of nanomaterials including sonolysis, sonochemical reduction, co-precipitation under ultrasound and ultrasonic microemulsion. Emphasis is focused on the main principles of ultrasound and the special features of the various methods.