AS Mohamed*
Diabetes mellitus (DM) is complex metabolic disorder which increases continuously worldwide. Type 2 diabetes mellitus is one of the most prevalence diseases worldwide. The mechanisms behind this disease are complicated and interfere with each other. The main defects in type 2 diabetes are an insulin resistant, decrease insulin secretion and increased hepatic glucose production. Each defect has many possible mechanisms. The purpose of this article is to review the possible mechanisms lead to development of type 2 diabetes.