Background/Aims: Youth with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency develop cardiovascular disease (CVD) risk factors of obesity and hypertension. Carotid intima-media thickness (CIMT), a marker of CVD risk, is increased in CAH young adults. We examined CIMT and its relationship with androgens and obesity in adolescents/young adults with CAH. Methods: Twenty CAH subjects (age 16 ± 3.3 years, 50% female) and 20 matched controls were studied cross-sectionally. Eight additional obese patients with CAH were included in within-group comparisons. CIMT by high-resolution ultrasound, androgens, anthropometry, bone age (BA), and metabolic/inflammatory markers were assessed. Results: Within the CAH group, CIMT correlated with 17-hydroxyprogesterone (r = 0.48, p < 0.05) and androstenedione (r = 0.46, p < 0.05), and was greater in obese subjects. CIMT was greater in CAH males than females, but similar among CAH females with advanced BA, CAH males with normal BA, and control males. There was no difference in CIMT between CAH and controls, although high-density lipoprotein was inversely correlated with CIMT in both groups. Conclusion: CIMT is associated with increased androgens in CAH adolescents and young adults, with loss of sex differences in CAH females with excess androgen exposure. Our findings highlight the importance of hormonal control for CVD prevention in CAH.