Objective: This study aimed to assess the relationship of cognition, depression and anxiety to glycemic control in elders with diabetes. DM is a chronic medical condition. Its control depends on adherence to medical therapy and making decisions related to lifestyle changes. This decision making capacity is affected by many factors including cognition and psychological status. Design: It was a case control study. Setting: It was done in Ain Shams University Hospital inpatients and DM outpatient clinic, Cairo, Egypt. Participants: Of the one hundred diabetic patients aged ≥ 60 years, 50 had Hemoglobin A1c (HbA1c) ≥ 7.5 (cases) and 50 had Hb A1c 7.5 (controls). Measurements: Cognition was assessed using minimental status examination (MMSE) test, Mattis Organic Mental Syndrome Screening Examination (MOMSSE) and Cambridge Cognitive Examination (CAMCOG) test. Geriatric depression scale-15 (GDS-15) was performed for depression assessment, while anxiety was assessed by DSM IV criteria. Laboratory investigations included: fasting blood sugar (FBS), post-prandial blood sugar (PPBS), glycated haemoglobin (Hb A1c), low density lipoprotein (LDL), high-density lipoprotein (HDL), total cholesterol, and triglycerides (TG). Results: Significant difference was found between the two groups regarding scores of cognitive tests: MMSE score (p = 0.004); below average (p = 0.02) and average scores (p = 0.05) of MOMSSE; CAMCOG score (p = 0.015); and CAMCOG divided items score including orientation (p = 0.003), comprehension (p = 0.005), expression (p = 0.020), attention (p = 0.002), and abstraction (p = 0.008) as well as depression screening scores (P = 0.002). Using Receiver Operating Characteristic, CAMCOG had better sensitivity and MOMSSE had better specificity. Conclusion: Cognitive impairment was associated with poor glycemic control, and impairment in attention and abstraction, related to executive function, functions were found to be associated with poor glycemic control. These functions may be more needed in self management of DM and hence affected glycemic control. Depression was associated with poor glycemic control but anxiety was not.