AbstractMay–Thurner syndrome refers to anatomic compression of the left iliofemoral vein by the overriding right iliac artery. We report three adolescents who presented to our pediatric hospital with iliac vein thrombosis and were diagnosed with May–Thurner syndrome. Each received catheter‐directed thrombolysis followed by balloon angioplasty to restore flow. Two patients had endovascular stents placed. The procedures were well tolerated, without major complications. Additional thrombophilic risk factors were identified in each patient. Though uncommon, pediatric hematologists should consider May–Thurner syndrome in adolescents who present with a left lower extremity thrombosis. Aggressive therapy may be warranted due to the risk of post‐thrombotic syndrome. Pediatric Blood Cancer 2006;47:834–838. © 2005 Wiley‐Liss, Inc.