Ipsilateral internal carotid artery bypass has been used successfully to treat aneurysms, infection, tumor, and occlusive disease. The purpose of this study was to evaluate the long-term outcomes of autogenous and prosthetic conduits used for ipsilateral internal carotid artery bypass. A retrospective review of a single-institution registry was performed to identify patients with ipsilateral carotid artery bypass. Demographics, complications, and patency were recorded and compared using χ2, Fisher's exact, and log-rank analysis. From 1994 to 2016, 105 patients underwent ipsilateral carotid artery bypass (86 prosthetic, 19 veins). The venous bypass group and prosthetic bypass group were different in terms of gender (8 males and 11 females vs 58 males and 28 females; P = .038), but similar in age (mean in the venous bypass group, 63 years [range, 18-80 years] vs mean in the prosthetic bypass group 68 years [range, 33-88 years], P = .052). The mean follow-up was 53 months (range, 1 month to 15 years). Diabetes, pulmonary disease, hypercholesterolemia, and tobacco use were not statistically different between the groups. Indications were different between the groups, with a prosthetic bypass being used more often for occlusive disease and a venous bypass used more often for infection, aneurysm, trauma, and tumor (Fisher's exact test, P = .004). Perioperative complications were few and similar between groups (restenosis, immediate occlusion, and neurologic morbidity). Patency rates, as determined by duplex ultrasound examination, were similar at 1 year (100% venous bypass group vs 99% prosthetic bypass group; P = .434). The 10-year follow-up with an estimated patency based on extrapolated survival curves to be 84% for the venous bypass group vs 88% for the prosthetic bypass group. Ipsilateral internal carotid artery bypass performed for a variety of indications using prosthetic and venous conduits have demonstrated excellent short-term results. Both types of conduits in this series have trended toward continued durability over long-term follow-up.