This report provides a detailed overview of diabetes mellitus, differentiating it from diabetes insipidus, and classifying diabetes mellitus into Type 1 and Type 2. It discusses the diagnosis and management strategies including non-pharmacological treatments, medication, and surgical options. The pathophysiology of insulin deficiency and its impact on glucose and fat metabolism are explained, along with the symptoms of diabetes mellitus such as glycosuria, polyuria, polydipsia, and weight loss. A graphical analysis of blood glucose levels in patients is presented, followed by a discussion of the long-term complications of diabetes mellitus, including diabetic retinopathy, kidney and heart disease, and diabetic foot disease. The report emphasizes the importance of considering these complications in designing effective management and treatment plans.