We have reported the ultrasonographic findings in a 9-year-old girl with torsion of a normal ovary. In this and six previously reported cases ultrasonography has shown hypoechoic, solid, intrapelvic masses sometimes containing small cysts. Liquid may be present in the pelvic cul-de-sac, and in one instance an anechoic halo surrounded an infarcted ovary. A second case, a seemingly false-positive ultrasonic diagnosis of ovarian enlargement, illustrated a possible pitfall. Ultrasonography can aid in earlier diagnosis of ovarian torsion, which may permit more ovaries to be salvaged.