Objective To evaluate the accuracy of multi-slice CT(MSCT) angiography in detection of carotid artery stenosis. Methods A total of 29 consecutive patients with known or suspected carotid artery disease were studied by MSCT. The results were compared with quantitative carotid angiography.Results In the 203 carotid arteries of 29 patients, 22 of 24 carotid arteries with significant stenosis ( ≥ 30% reduction of vessel diameter) were correctly detected by MSCT,and 171 of 179 carotid arteries with normal or mild stenosis ( ＜ 30% reduction of vessel diameter) were correctly detected by MS CT. These values corresponded to sensitivity of 91.7% (22/24), specificity of 95.5% (171/179), positivè predictive value of 73.3% (22/30), and negative predictive value of 98.8% ( 171/173 ) for the detection of significant carotid artery stenosis by MSCT. In the 203 carotid arteries of 29 patients, 14 of 14 carotid arteries with high-grade stenosis were correctly detected by MSCT,and 186 of 189 carotid arteries with normal or mild stenosis were correctly detected by MSCT. These values corresponded to sensitivity of 100.0%(14/14), specificity of 98.4% (186/189), positive predictive value of 82.4% (14/17),and negative predictive value of 100.0%(186/186) for the detection of high-grade carotid arteries stenosis by MSCT. Conclusions MSCT angiography shows significant carotid artery stenosis with high accuracy. It may be used as an alternative for carotid angiography in detection of carotid artery stenosis.