Cholesterol is a fatty substance (lipid) classified as a waxy steroid of fat. It is absorbed by the intestine into blood stream and is packaged inside a protein coat a chylomicron. Blood glucose is a simple monosaccharide absorbed directly into the blood stream during digestion. The level of blood glucose normally represents a balance between the inflow of glucose into blood and it is uptake by the tissue. Atherosclerosis is a general term for a number of different medical conditions that affect the heart, this is occurs when the blood supply to a part of heart is interrupted, must commonly due to plaque, is build up in the coronary arteries consist of lipid cholesterol and calcium. It causes a damage of potential disease of heart muscle due to thickening and hardening of arteries. Diabetes mellitus is a disorder in which the level of blood glucose is persistently elevated above the normal range due to decrease secretion of insulin. The main objective of this study is to determine the concentrations of total cholesterol and glucose into blood serum of Iraq patients with atherosclerosis and diabetes mellitus type 2. This study included 60 specimens of patients with atherosclerosis and 60 patients with type 2 diabetes mellitus; their age range was 45-65 years. These patients were then matched by age and sex to 30 healthy individuals. Results revealed that there was highly significantly increased in the mean value of total cholesterol and glucose concentrations in patients of atherosclerosis (p<0.001) and diabetes mellitus (p<0.001) as compared with healthy individuals.