Ultrasonography is the use of high-frequency sound waves to generate an image. Because ultrasonography is relatively safe and noninvasive, it has become a useful diagnostic tool in veterinary medicine. Sonographers, especially those who wish to learn how to perform ultrasound examinations, should have a basic understanding of ultrasonography: how sound waves are produced and interact with tissue, what types of images can be obtained, how to get the best image, and how to identify common artefacts.