Widespread use of ultrasound in early pregnancy has led to the detection of incidental, asymptomatic ovarian masses more frequently. The diagnosis, follow up and treatment of ovarian masses in pregnancy are challenging. Although the most commonly detected lesions are benign such as protracted corpus luteal cyst, benign cystic teratoma and benign or borderline cystadenoma and Carcinomas of the ovary are rare but aggressive due to the high circulating hormones of pregnancy. The incidence of adnexal masses is 1-2% of pregnancies. It is estimated that 10 % of adnexal masses that persist throughout pregnancy are malignant. Although advances in ultrasound (US) technology have enabled better characterization of ovarian masses, there are particular indications of magnetic resonance imaging (MRI).MRI quality can be limited by artifacts caused by fetal movement and the mothers inability to lie flat safely. Gadolinium enhanced MRI is not recommended in pregnancy. However, in pregnancy CA125 is elevated in the first trimester but can be used in advanced pregnancy and for follow up as a biochemical marker for malignancy. Acute adnexal mass complications include hemorrhage, torsion and rupture, with the patients most commonly presenting with acute pelvic pain. Surgical management is not recommended during the first trimester, but has to be considered if malignancy is suspected or acute complications occur. Surgery is associated with spontaneous miscarriage, rupture of membranes and preterm labour. Hence accurate characterization is paramount to distinguish between benign and malignant adnexal masses. The aim of this lecture is to emphasize the presentation, imaging and management of ovarian masses during pregnancy.