Objective To investigate the association between time in range (TIR) and diabetic retinopathy (DR) among patients with type 2 diabetes mellitus (T2DM). Methods This study was designed as a prospective cohort study. A total of 1 057 patients with T2DM were prospectively recruited from April 2005 to May 2019 from Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People′s Hospital. TIR was measured with continuous glucose monitoring (CGM) at baseline. Cox proportion hazard regression analysis was used to determine the association between TIR and the risk of DR. Results During a median follow-up of 7.7 years, 266 patients developed DR. The incidence rates of DR were 26.0 (63/2 419.7), 28.0 (57/2 032.9), 40.5 (79/1 950.8) and 42.0 (67/1 594.1) per 1 000 person-years in TIR>85%, 71%-85%, 51%-70%, and ≤50%, respectively (log-rank P=0.013). Cox proportion hazard regression analysis showed that after adjusting for sex, age, diabetes duration, smoking, body mass index, blood pressure, blood lipids, and estimated glomerular filtration rate, hazard ratios (HR) for DR across different levels of TIR (>85%, 71%-85%, 51%-70%, and ≤50%) were 1.00, 1.02 [95% confidence interval (CI) 0.71-1.46], 1.42 (95%CI 1.01-1.99) and 1.46 (95%CI 1.02-2.07), which had statistically significant differences (P for trend=0.01), respectively. When TIR was considered as a continuous variable, the multivariable-adjusted HR for DR associated with each 10% decrease in TIR was 1.07 (95%CI 1.02-1.13). Conclusion The current prospective cohort study indicated an association of lower TIR with an increased risk of DR among patients with T2DM, supporting the validity of TIR as an optimal marker of glucose control. [ABSTRACT FROM AUTHOR]