A 4 year old female with acute lower abdominal pain was admitted with the diagnosis of periappendiceal abscess made by ultrasonography. At laparotomy, the appendix was normal, but the left ovary was twisted and necrotic. Appendectomy and left salpingo-oophorectomy were performed. The pathology of the appendix was normal, and the left tube and ovary were ischemic and had hemorrhagic necrosis. Pediatric adnexal torsion may be difficult to diagnosis clinically. Sonography is the preferred imaging study. It usually confirms a pelvic mass but may not establish the diagnosis. The correct diagnosis of adnexal torsion is often made at exploration. The most common erroneous diagnosis is acute appendicitis or periappendiceal abscess. Therapy for adnexal torsion remains controversial. While extirpation has been the standard of treatment in the past, there are current proponents of conservative therapy with adnexal sparing. Early diagnosis may lead to more frequent salvage of affected adnexa.