Introduction: Adnexal torsion in advanced pregnancy is an uncommon emergency. Torsion usually occurs in ovaries with functional cysts or tumors. It is uncommon for a normal-sized ovary to undergo torsion in advanced gestation. We report torsion of a normal-sized ovary in the third trimester of pregnancy, most probably the first case report of its kind in the English-language literature. Case presentation: A 32-year-old Omani woman at 32-weeks gestation (gravida 2 para 1) was admitted with right iliac fossa pain, nausea and vomiting of 2 days duration, as well as a history of a similar episode one month earlier. On examination, a provisional diagnosis of appendicitis was made. Laparotomy revealed, however, that the right ovary was gangrenous and had undergone torsion. Conclusion: Adnexal torsion, though rare, should be kept in mind in the differential diagnosis of lower abdominal pain in advanced gestation. Although in our patient, the affected ovary could not be saved, an early diagnosis using imaging like Doppler of the adnexae will enable early intervention to save the ovaries of the patient, especially in young women.