Patch angioplasty after carotid endarterectomy has been advocated to improve results by decreasing the incidence of recurrent stenosis and postoperative carotid thrombosis. Aneurysmal and infectious complications may be secondary to use of prosthetic materials in arterial reconstruction. We report four patients who developed late operative site complications related to carotid patching. All four of our patients had delayed pseudoaneurysms and three had infection related to the Dacron patch. In a typical case, a 57-year-old who had a right carotid endarterectomy in 1994 presented with a 1-month history of an enlarging right neck mass 7 years later. Imaging revealed a 6 x 4 cm pseudoaneurysm originating from an opening between the patch graft and the old endarterectomized carotid wall. Analysis of the literature disclosed an additional 45 patients who had pseudoaneurysms and/or infection related to carotid patching, most frequently with Dacron. We postulate that a low-grade Staphylococcus epidermidis infection of the foreign body patch may be the etiology. Autogenous saphenous vein interposition graft and antimicrobials effective against gram-positive organisms corrected the pseudoaneurysm. Although the benefits of routine carotid patching may include a decrease in restenosis, this advantage must be weighed against the risk of late pseudoaneurysm and/or infection when a prosthetic patch is used to closed the endarterectomy site.