The authors present 6 unusual vascular complications secondary to maldeployed or undeployed vascular stents. They retrospectively reviewed patients referred for complications of vascular stent placement from September 1998 to March 1999. Information on patient history was obtained from a computerized database and clinical document file. Radiographic information was obtained from arteriograms, ultrasound, and computed tomography imaging. Case 1 describes an undeployed stent in the superior mesenteric artery with subsequent thrombosis in addition to celiac occlusion secondary to attempted balloon angioplasty. Case 2 refers to a malpositioned stent placed in the aortic arch and proximal left common carotid artery. Case 3 involves an undeployed coronary stent that migrated to the right distal posterior tibial artery, causing vascular occlusion and chronic pain. In Case 4, an attempted stent placement into the left iliac artery resulted in an undeployed stent lodged across the aortic bifurcation. Case 5 illustrates a partially deployed stent occluding the left renal artery that was unamenable to further angioplasty. Case 6 demonstrates arterial dissection with a pseudoaneurysm following stent placement for right subclavian stenosis. Five patients required operative intervention. Increased use of stents may escalate the number of complications requiring operative intervention. Foreign bodies can migrate distally and potentiate thrombotic occlusion of vessels. Caution must be used not only at the time of deployment but also in the follow-up period. Continued surveillance becomes important after vascular stent placement.