OBJECTIVE: Glycated hemoglobin was recently recommended for use as a diagnostic test for diabetes. We examined the association between 2010 American Diabetes Association diagnostic cut points for glycated hemoglobin and microvascular outcomes (chronic kidney disease, end-stage renal disease [ESRD], and retinopathy) and formally tested for the presence of risk thresholds in the relationships of glycated hemoglobin with these outcomes. RESEARCH DESIGN AND METHODS: Prospective cohort and cross-sectional analyses of 11,357 participants (773 with a history of diagnosed diabetes) from the Atherosclerosis Risk in Communities (ARIC) Study. RESULTS: During a median of 14 years of follow-up of individuals without diagnosed diabetes at baseline, clinical categories of glycated hemoglobin were associated with risk of chronic kidney disease, with adjusted hazard ratios (HRs) of 1.12 (0.94 -1.34) and 1.39 (1.04 -1.85) for glycated hemoglobin 5.7- 6.4% and <6.5%, respectively, as compared with <5.7% (P trend = 0.002). The corresponding HRs for ESRD were 1.51 (0.82-2.76) and 1.98 (0.83- 4.73), respectively (P trend = 0.047). In the absence of diagnosed diabetes, glycated hemoglobin was cross sectionally associated with the presence of moderate/severe retinopathy, with adjusted odds ratios of 1.42 (0.69 -2.92) and 2.91 (1.19 -7.11) for glycated hemoglobin 5.7-<6.5% and ≥6.5%, respectively, compared with <5.7% (P trend = 0.011). Risk associations were stronger among individuals with a history of diabetes. We did not observe significant thresholds in the associations of glycated hemoglobin with kidney disease risk or retinopathy. CONCLUSIONS: These data from a community-based, biracial population support the use of new 2010 American Diabetes Association glycated hemoglobin cut points for the diagnosis of diabetes.