An 28 years old women came on his 7. post partum day with an lower abdominal pain on the right hand side with the diagnosis of an unilateral rotating ovarian tumor. After computed tomography, ultrasound and laparoscopy the adnectomia dextra by laparotomy was performed. In the histology we find an ovarian vein thrombosis. The following therapy was made with an therapeutic anticoagulation with heparin combined with an antibiotic therapy and later with an oral anticoagulation.