Aim Diabetes mellitus is a chronic medical condition that is dependent on adherence to medical therapy and making decisions related to lifestyle changes. This decision‐making capacity is under the control of a specific domain of cognitive function known as executive function. The purpose of the present study was to evaluate the frequency rate of executive dysfunction among elderly diabetic patients and to assess its association with glycemic control. Method This was a cross‐sectional study. The study was carried out with 1200 diabetic older adults aged 60 years or older visiting the specific diabetes care outpatient clinics of Ain Shams University Hospital and Ain Shams Specialized Hospital, Cairo, Egypt. Executive function was evaluated using the animal verbal fluency test (AVF), clock drawing test (CDT) and digit span backward (DSB). Glycemic control was assessed by measuring hemoglobin A1c (HbA1c). Results The frequency rate of executive dysfunction among elderly diabetic patients is 55%. There were negative correlations between HbA1c and AVF (r = −0.570, P = 0.001), CDT (r = −0.191, P = 0.014), DSB (r = 0.282, P = 0.002) and medication adherence (r = −0.365, P = 0.001). Positive correlations were detected between HbA1c and diabetes duration (r = 0.424, P = 0.020), body mass index (r = 0.194, P = 0.012), and Geriatric Depression Scale (r = 0.380, P = 0.030). Conclusion Executive dysfunction is extremely common among elderly diabetic patients and it is significantly associated with poor glycemic control. Geriatr Gerontol Int 2014; ●●: ●●–●●.