Background: Diabetes is a chronic, lifelong disease that affects the ability to use food as both fuel and energy for survival and characterized by hyperglycemia resulting from impaired insulin secretion, insulin action, or both. Diabetic retinopathy is also a complication of diabetes and is rapidly becoming a global health problem that can jeopardize a patient's vision and visual function. Therefore the aim of this study was to identify the determinants of progression of fasting blood sugar level and time to occurrence of diabetic retinopathy. Methods: Institution-based retrospective follow-up study was conducted to obtain relevant data on type 2 diabetes patients at Debre Markos referral hospital. We presented a joint model that consists of two related sub-models: a Weibull model for the time to occurrence of diabetic retinopathy and a linear mixed effect model for the progression of fasting blood sugar level. Results: The prevalence rate of diabetic retinopathy was 18.2% of observations with median follow-up time of 17 months. The slope of change in fasting blood sugar is significantly associated with the hazards of time to diabetic retinopathy (aHR: 1.001; 95%CI: 1.003, 1.009). The analysis also showed that older age (aHR:4.119; 95%CI: 4.116, 4.284), male (aHR:5.037; 95%CI: 2.633, 10.496), longer duration of diabetes (aHR:3.133; 95%CI: 1.815, 5.686), higher glycemic control (aHR:2.769; 95%CI: 1.835, 4.162) were significantly associated with a high risk of diabetic retinopathy. Furthermore, increasing time, high blood pressure, taking many medications, high Creatinine levels, and longer diabetes duration significantly increased blood sugar levels. Conclusion: Our study investigated the joint effect of fasting blood sugar level and time to diabetic retinopathy, and its association with age, sex, duration, glycemic control, Creatinine level, and HBA1C. From a methodological point of view, we can conclude that the joint model approach provides extensive information about progression of disease and time to occurrence of disease. We hope that our results will help applied researchers become familiar with the model, including how to interpret the results. Keywords: Type 2 diabetic mellitus, Diabetic Retinopathy, Fasting Blood Sugar