Cognitive impairment, poor sleep quality, Alzheimer's disease and dementia are complications of uncontrolled type 1 diabetes (T1D). Melatonin; a hormone secreted from the pineal gland; previously associated with sleep and cognition; has recently been associated with insulin secretion and glucose homeostasis. People with diabetes have low serum melatonin levels. Moreover, melatonin adminstration was found to decrease anxiety, depression signs, and glycated hemoglobin (HbA1c) in diabetic rats . Hence, this study assessed the effect of melatonin adminstration add on therapy on excecutive functions, sleep quality and glycemic metrics among adolescents with T1D.