Ovarian vein trombosis (OVT) is a pathologic entity classically considered as a postpartum complication and only rarely associated with other diseases. Due to its vague symptoms, it is usually underdiagnosed. However its consequences can be fatal. We report a case of an incidental finding of ovarian thrombosis in an asymptomatic 45-year-old woman who underwent surgery due to the ultrasonographic finding of a para-ovarian cyst.