Background-Chronic kidney disease (CKD) increases cardiovascular disease (CVD) risk. However, the association of mildly reduced kidney function with CVD risk is unclear. Methods and Results-This study investigated the association of estimated glomerular filtration rate (eGFR) with prevalent CVDs, 10-year Framingham risk for coronary heart disease (CHD), and 10-year risk of atherosclerotic cardiovascular diseases (ASCVD) in 239 832 participants from the baseline of the Risk Evaluation of cAncers in Chinese diabeTic Individuals: a lONgitudinal study. With an interviewer-assisted questionnaire, we collected information on CVD, including reported CHD, stroke, or myocardial infarction. Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation was used to calculate eGFR. Compared with individuals with normal eGFR (>= 90 mL/min per 1.73 m(2)), those with decreased eGFR (75-89, 60-74, and <60 mL/min per 1.73 m(2)) had higher risk of prevalent obesity, diabetes mellitus, hypertension, and dyslipidemia in both men and women (P for trend all <0.001). Moreover, a significantly higher 10-year Framingham risk for CHD and 10-year risk for ASCVD was observed in both men and women with mildly decreased eGFR (60-89 mL/min per 1.73 m(2)). Conclusions-Even mildly reduced eGFR (under 90 mL/min per 1.73 m(2)) is associated with elevated 10-year Framingham risk for CHD and 10-year ASCVD risk among Chinese adults.