AIM: To evaluate the influence of food habits, specifically adherence to the Mediterranean diet, on carotid intima-media thickness (CIMT) and the presence of plaques in HIV-infected patients taking antiretroviral therapy (ART) and non-HIV-infected participants and to determine if HIV infection contributes independently to subclinical atherosclerosis. ----- METHODS: We conducted a cross-sectional study of 110 HIV-infected patients on ART and 131 non-HIV-infected participants at the University Hospital for Infectious Diseases in Zagreb, Croatia, from 2009-2011. CIMT measurement and determination of carotid plaque presence was detected by ultrasound. Adherence to the Mediterranean diet was assessed by a 14-point food-item questionnaire. Subclinical atherosclerosis was defined by CIMT≥0.9 mm or ≥1 carotid plaque. ----- RESULTS: In HIV-infected patients, subclinical atherosclerosis was associated with older age (Plt;0.001; Mann-Whitney test), higher body mass index (P=0.051; Mann-Whitney test), hypertension (Plt;0.001; χ(2) test), and a lower Mediterranean diet score (P=0.035; Mann-Whitney test), and in non-HIV-infected participants with older age (P lt; 0.001; Mann-Whitney test) and hypertension (P=0.006; χ(2) test). Multivariate analysis showed that decreased adherence to the Mediterranean diet was associated with higher odds of subclinical atherosclerosis (odds ratio [OR] 2.28, 95% confidence interval [CI] 1.10-4.72, P=0.027) as was current smoking (OR 2.86, 95% CI 1.28-6.40), hypertension (OR 3.04, 95% CI 1.41-6.57), and male sex (OR 2.35, 95% CI 0.97-5.70). There was a significant interaction of age and HIV status, suggesting that older HIV-infected patients had higher odds of subclinical atherosclerosis than controls (OR 3.28, 95% CI 1.24-8.71, P=0.017 at the age of 60 years). ----- CONCLUSION: We confirmed the association between lower adherence to the Mediterranean diet and increased risk of subclinical atherosclerosis and found that treated HIV infection was a risk factor for subclinical atherosclerosis in older individuals.