Background: Adipose tissue is an endocrine organ that secretes a large number of proteins under normal and pathophysiological conditions. Resistin, a new adipocyte hormone described as low-molecular weight, adipokine as member of a cysteine-rich secretory protein family. It was found to be predominantly expressed in adipocytes, to mediate insulin resistance and to show increased circulating levels in obesity (Li et al, 2009). Objectives of the Study: In the current study we aimed at investigating the level of circulating Resistin in people with type 2 diabetes mellitus in comparison to those without type 2 DM who presented to the emergency department with Non-ST segment Elevation Myocardial Infarction (Non-STEMI). Subjects and Methods: The study was carried out on twenty patients suffering from Non-STEMI, with ten patients had type 2 DM (group 1) and ten patients were non-diabetic (group 2). Serum Resistin was measured in these patients while they were just admitted in different ICU departments in Kasr El-Aini Hospital, including medical ICU of department 6, cardiology department (department number 23) CCU and internal medicine hospital medical ICU. Other parameters were included in the study as the age, sex, body mass index (BMI), lipid profile and cardiac enzymes, admission random blood glucose and HBA1C in relation to the serum Resistin levels. This was in comparison with 20 healthy controls (group 3) where history and physical examination were done beside anthropometric measures and Resistin. (Group 2 and group 3) were diagnosed as non diabetic either by random blood sugar less than 200 mg/dl or HBA1C less than 6.5% and these laboratory data were done either during evaluation of controls or recently during their routine evaluation by the primary physician. Results: Resistin was found to be statistically highly significantly correlation with presence of type 2 DM in NON-STEMI patients (group 1) with P-value less than 0.001 than in (group 2). Resistin had statistically highly significantly correlation in cases (group 1+2) than in controls (group 3). Resistin was positively correlated with troponin, CK, CKMB, admission capillary blood glucose and HBA1C. There was no correlation with lipid profile (cholesterol, LDL and HDL) or BMI. Conclusions: Resistin was found to be positively correlated with presence of type 2 DM and with higher admission capillary blood glucose and also with the long term Diabetic control as presented by HBA1C. In the same time, Resistin was positively correlated with presence of NON-STEMI especially in diabetic patients and with the level of cardiac enzymes. This confirms the diagnostic and prognostic role of Resistin as inflammatory marker and adipokine.