Background: Diabetes Mellitus (DM) is a major 21 st century health and development challenge, this chronic and incurable non-communicable disease is large preventable but remains responsible for millions of deaths annually and many more life-threatening complications. Uncontrolled diabetes and poor diabetic patients' knowledge about disease can lead to a high morbidity and mortality. Aim of the Study: To evaluate the effect of nursing Instructions on adherence of diabetic patients to treatment. Research Design: A quasi-experimental design was utilized in this study. Setting: The study was conducted in outpatient clinic for diabetic follow up at Minia University Hospital and Minia General Hospital. Sample: A purposive sample of 144 adult with type two diabetes mellitus (T2DM) were divided in to two equal groups (study and control) from both sex with duration of diabetic disease more than one year and patients without comorbid disease, and without cerebrovascular accident. Tools of Data Collection: Structured Interview assessment questionnaire sheet (patient socio-demographic characteristics and medical data), Assessment Scale for Treatment Adherence to assess Compliance of T2DM to Diabetic management, and instructions about diabetes "Booklet". Results: Current study findings revealed that there was a highly a significant improvement in Compliance of T2DM patients to Diabetic management in study group than control group and in post 1st and 2nd follow up for study group than pre application of instructions. Conclusion: The diabetic instructions and the use of booklet would improve patient's Adherence to Treatment. Recommendations: Nurses should emphasis to provide instructions tailored to each diabetic patient and increase their awareness about the importance of diabetic instruction to improve glycemic control.