Ovarian vein thrombosis (OVT) is a rare complication of pregnancy. However, recognition and treatment is critical because a delay in diagnosis could lead to significant maternal morbidity. The diagnosis of OVT remains a challenge because there is no known profile of risk factors. Current controversies concern radiologic diagnosis, appropriate treatment strategies including antibiotics and anticoagulation, treatment duration, and testing for thrombophilias. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians. LEARNING OBJECTIVES: After completion of this article, the reader should be able to explain that even though the occurrence of postpartum ovarian vein thrombosis (OVT) is rare the physician must consider it in a differential diagnosis in a patient with postdelivery fever unresponsive to antibiotics, state that missing the diagnosis can have devastating consequences, and recall that at times it is difficult to differentiate from septic thrombophlebitis.