BACKGROUND Numerous studies have confirmed the effectiveness of slowing the progression of atherosclerosis by blood pressure (Bp) control in patients with hypertension and several studies also showed the efficacy of intensive glycemic control in decreasing progression of carotid intima-media thickness (CIMT) in patients with type 1 and type 2 diabetes. However, few studies have compared the relative importance of glycemic vs. Bp control in patients with diabetes and hypertension. We aimed to investigate the association between Bp and glycemic control and subclinical carotid atherosclerosis in older patients with hypertension and type 2 diabetes. METHODS In a cross-sectional study, B-mode high-resolution ultrasonography of the carotid artery was performed in 670 subjects (508 males and 162 females) aged 60 years or over who had self-reported hypertension and diabetes but no history of coronary heart disease or stroke. Subjects were categorized by their systolic blood pressure: tight control, < 130 mmHg; usual control, 130-139 mmHg; or uncontrolled, ≥ 140 mmHg, and by their hemoglobin A1c (HbA1c) level: tight control, < 6.5%; usual control, 6.5%-7.5%; or uncontrolled, ≥ 7.5%, respectively. RESULTS The mean CIMT was 8.20 ± 0.11 mm, and carotid plaque was found in 52.5% (352/670) subjects. Overall, 62.1% of the subjects had subclinical carotid atherosclerosis, defined as having either carotid plaque or elevated CIMT (≥ 1.1 mm). The mean CIMT was significantly different between Bp control categories (7.60 ± 0.09 mm, 7.90 ± 0.08 mm, and 8.60 ± 0.12 mm, respectively, P = 0.03) but not between glycemic control categories (8.20 ± 0.10 mm, 8.1 ± 0.08 mm, and 8.40 ± 0.14 mm, respectively, P = 0.13) using ANCOVA analysis. Multivariable logistic regression adjusting for potential confounding factors showed that usual or uncontrolled Bp control were associated with having carotid plaque (OR = 1.08 and OR = 1.42, respectively), or elevated CIMT [Odd ratio (OR) = 1.17, 95% confidence interval (CI) 1.04-2.24, and OR = 1.54, 95% CI 1.36-2.96, respectively compared to tight Bp control; but did not show glycemic control as independent predictor of either having carotid plaque or elevated CIMT. CONCLUSIONS In older patients with hypertension and diabetes, blood pressure control, but not glycemic control is associated with subclinical carotid atherosclerosis.