Thromboembolic events are one of the important extraintestinal manifestations of inflammatory bowel diseases that are associated with considerable morbidity and mortality. Iliac vein thrombosis is rarely reported in inflammatory bowel diseases. A 9.5 year-old girl was presented with joint pain, nausea, vomiting and weight loss. She was diagnosed with Crohn's disease and right internal iliac vein thrombosis. With the implementation of immunosuppressive and anticoagulant therapies clinical picture has improved and thrombosis has resolved. Timely diagnosis and early treatment of extraintestinal complications of inflammatory bowel diseases might be lifesaving. (C) 2010 European Crohn's and Colitis Organisation. Published by Elsevier B.V. All rights reserved.