Twenty patients with pelvic abscesses diagnosed either at surgery or from typical clinical findings underwent sonography. Seventeen of the twenty patients had inflammatory processes of gynecological origin. In the main, two patterns were observed. The more common pattern was a small, round adnexal or cul de sac mass with a slightly irregular border. The other pattern consisted of large, rough-bordered, multilocular masses that obscured the uterus. In single cases confusion had occurred between pelvic abscesses, fibroids, and chronic ruptured tubal pregnancy. The role of ultrasound in the management of patients with tubo-ovarian abscesses is discussed.