OBJECTIVES: To evaluate the predictive role of carotid stiffening, quantified using ultrafast pulse wave velocity (ufPWV), for assessing cardiovascular risk in young populations with no or elevated cardiovascular risk factors (CVRFs). MATERIALS AND METHODS: This study enrolled 180 young, apparently healthy individuals who underwent ufPWV measurements. They were classified into three groups: the CVRF-free group (n = 60), comprising current non-smokers with untreated blood pressure < 140/90 mmHg, fasting blood glucose (FBG) < 7.0 mmol/L, total cholesterol (TC) < 6.2 mmol/L, low-density lipoprotein < 4.1 mmol/L, and high-density lipoprotein ≥ 1.0 mmol/L; the CVRF-optimal group (n = 54), including those with untreated blood pressure < 120/80 mmHg, TC < 5.2 mmol/L, and FBG < 5.6 mmol/L; and the atherosclerosis (AS)-risk group (n = 66), with participants who did not meet the aforementioned criteria. Adjusted odds ratios (ORs) with 95% confidence intervals and ordinal logistic regression models were used. RESULTS: Carotid stiffening significantly differed among CVRF groups at both participant and carotid levels, and across age, sex, and carotid intima-media thickness subgroups (all p < 0.05). Carotid stiffening significantly correlated with age (r up to 0.464, p < 0.001) and BMI (r up to 0.502, p < 0.001) overall, in CVRF groups, and in men and women. Increased carotid stiffness was associated with elevated CVRFs in young populations, with the OR of 2.21-7.71, independent of major CVRFs. CONCLUSION: ufPWV-estimated carotid stiffening can be a promising tool for early detection of cardiovascular risk in young populations with no or elevated CVRFs. KEY POINTS: Question What is the association between cardiovascular risk, as characterized by exposure to varying levels of cardiovascular risk factors (CVRFs), and carotid stiffening in young populations? Findings Ultrafast pulse wave velocity (ufPWV)-estimated carotid stiffening is associated with cardiovascular risk in young populations with optimal, normal, and elevated CVRFs, independent of major CVRFs. Clinical relevance ufPWV can be a promising quantitative predictor for assessing cardiovascular risk in young people. Its potential discrimination helps improve the understanding of early atherogenesis and guides the clinical assessment of enhanced cardiovascular risk in adults under 40 years of age.