May-Thurner syndrome is associated with deep vein thrombosis resulting from chronic compression of the iliac vein against the lumbar vertebrae caused by the overlying common iliac artery. Stent insertion into the compressed lesion is used in treatment of May-Thurner syndrome. Various complications can occur during angioplasty while using a stent. Among these complications, shrinkage of the vein below the stent, a rare complication, was observed in our hospital during treatment of a patient with May-Thurner syndrome. Different complications can occur when venous angioplasty is performed, unlike that when arterial angioplasty is performed.