Purpose: To assess retinal vessel diameter in adult Chinese with and without glaucoma. Methods: The population-based, cross-sectional study included 4439 of the 5324 subjects asked to participate (response rate 83.4%), all aged 40 years or older. This study was divided into a rural part (1973 subjects [44.4%]) and an urban part (2466 subjects [55.6%]). Colour optic disc and fundus photographs were morphometrically examined for 2418 subjects. The retinal vessel diameters were measured at the optic disc border and at a distance of 2 mm to the optic disc border. The main outcome measure was the retinal vessel diameter. Results: Diameters of the retinal arteries were significantly (P < 0.001) the widest in the temporal inferior region, followed by the temporal superior region (P < 0.001), the nasal superior region (P < 0.001) and finally the nasal inferior region. Except for the nasal inferior vein, the same held true for the retinal veins. The sequence of the main four vessel trunks with respect to their diameters was not associated with age, gender or hyperopia versus myopia. The artery diameters showed a tendency to decrease in older age, while the vein diameters decreased across all age groups. Eyes with glaucomatous optic nerve damage showed significantly (P < 0.001) thinner arteries while the retinal vein diameters were not different. Conclusions: Diameters of the retinal arterioles and veins are the widest in the temporal inferior arcade, followed by the temporal superior arcade, the nasal superior arcade and finally the nasal inferior arcade. Retinal artery diameters decrease with glaucoma, and retinal vein diameters decrease with age.