Abstract: Background: Obesity is highly associated with insulin resistance and the increased risk of type 2 diabetes and cardiovascular diseases. Visfatin is a cytokine that is highly expressed in visceral fat. It's expression in visceral fat is increased in obese subjects. Visfatin exerts insulin-mimetic effects and was as effective as insulin in reducing hyperglycemia in insulin-deficient diabetic mice. Objective: To study serum visfatin level in patients with type2 diabetes mellitus and to clarify its possible relationship with insulin resistance and glycemic control. Patients and Methods: Eighty cases (60 type2 diabetic patients and 20 apparently healthy subjects) were subjected for estimation of visfatin and fasting insulin by ELISA technique together with routine laboratory investigations including fasting blood glucose, cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol and HbA1C. Results: Fasting blood glucose, fasting insulin level, HOMA-IR, HbA1C and visfatin levels were significantly higher in diabetic than control group. HBA1C, fasting serum glucose and serum visfatin were significantly higher in uncontrolled than controlled diabetic subgroups. Weight, BMI and serum visfatin were significantly higher in overweight diabetic subgroup than normal BMI diabetic subgroup. A positive significant correlation was found between serum visfatin & HbA1C levels in the diabetic group. Conclusion: The increased serum visfatin concentration may be a compensatory mechanism aimed at ameliorating the functional consequences of insulin deficiency. The increased visfatin concentration may also promote insulin sensitivity by its stimulatory effects on insulin receptors. [Osama S. El-Shaer; Khaled M. Belal; Hesham A. Issa and Tawfik El-Adl. Increased Serum Visfatin Levels in Patients with Type 2 Diabetic Patients. Life Sci J 2012;9(3):114-120]. (ISSN: 1097-8135). http://www.lifesciencesite.com. 15