Background: Diabetes mellitus is a global metabolic disorder characterized by persistent hyperglycemia and increased risk of microvascular and macrovascular complications. Consistent elevation of HbA1c can be associated with functional and structural changes in hemoglobin molecule, cytoplasmic viscosity and osmotic disturbances within red cell. These changes may be reflected in the red cell analytical parameters. Methods: 120 subjects were studied. 41 were non diabetic healthy subjects (Group1). 79 were known diabetic patients, divided into two groups: HbA1c 7(40 subjects) Group 3. Sample for glucose estimation and CBC were collected in vacutainers containing sodium Fluoride and K 2EDTA respectively. Glucose, HbA1c and CBC estimation was carried out by auto analyzers. Result: Mean RBC count of diabetics with HbA1c 7 when compared to non diabetic individuals. There was significant decrease in mean Hb, HCT, MCV, MCH of diabetics with HbA1c >7 when compared to diabetics with HbA1c