Introduction. Human immunodeficiency virus (HIV) infection provides patients an increased vascular risk, related to tradi-tional vascular risk factors and metabolic and vascular disease induced by antiretroviral treatment and HIV infection itself. Methods. By reviewing current literature, this article analyses meaning and measurement of subclinical atherosclerosis in general population; factors inducing vascular risk in HIV infected patients; and published evidence about subclinical atherosclerosis in this population. Results. Carotid ultrasound measurement of carotid intimamedia thickness and atherosclerotic plaques, as surrogate markers of vascular risk, allows non-invasive quantification of subclinical atherosclerosis and it predicts vascular risk, of acute myocardial infarction or stroke. Studies in HIV-infected patients show different results, due to methodological heterogeneity that difficults comparisons. Most studies found a higher degree and progression of subclinical carotid atherosclerosis in HIV positive patients, compared to non-infected HIV controls, and it is associated to classical vascular risk factors, antiretroviral treatment and HIV infection itself. Conclusion. Carotid ultrasound in HIV patients could stratify vascular risk in these patients and it represents an efficacious tool in atherosclerosis study.