Background: Diabetes mellitus is a metabolic disorder with varied etiologies characterized by chronic hyperglycemia and carbohydrate, fat and protein metabolism disorders caused by insulin secretion defect, insulin action or both. People with diabetes also have an increased risk of other diseases, including heart, peripheral, arterial and cerebrovascular disease. Objective: This study aimed to identify adherence of patients with insulin-dependent diabetes to therapeutic regimen. Patients and methods: A descriptive research design was used to accomplish the aim of the present study. A convenience sample of 150 adult patients who were admitted to the study. The study was conducted at the DiabeticOutpatient Clinic at Shark El Madina Hospital in Alexandria. Outpatient clinic was working 6 days per week from Saturday to Thursday from 9 am to 1 pm. Results: There was a highly statistical significant relation between patient's age, sex, level of education, monthly income and overall adherence to therapeutic regimen (p < 0.05). The highest percentage of the studied patients who had good adherence to therapeutic regimen were aged 40 -50 years old, female patients, university educated and had enough income (63.9%, 52.7%, 62.1%, and 75% respectively). Overall adherence barriers were moderate in the patient's age group of 50-60, male, manual occupation, divorced, secondary educated and who hadn't have enough income (65.4%, 55.9%, 71.1%, 71.4%, 70% and 63% respectively). Conclusion: Based on the study findings, it can be concluded that, more than half of the studied patients were fair adherent to diabetic diet, and more than two thirds of them were good adherent to medication.