This document comprises a review of data, which are concerned with the effects of ultrasound exposure on biological systems, and are pertinent to the evaluation of health risks for man. The purpose of this criteria document is to provide information for health authorities and regulatory agencies on the possible effects of ultrasound exposure on human health and to give guidance on the assessment of risks from medical, occupational, and general population exposure to ultrasound. Subjects briefly reviewed include: the physical characteristics of ultrasound fields; measurement techniques; sources and applications of ultrasound; levels of exposure from devices in common use; mechanisms of interaction; biological effects; and guidance on the development of protective measures such as regulations or sate-use guidelines.