In the last 30 years many research showed that high serum cholesterol level is a great risk for the atherosclerosis. In recent years, it has become clear that the immune system has a major role in atherosclerosis development and progression, and has binding capacity to cholesterol as well. It has been demonstrated in animal experiments, that anti-cholesterol antibodies (ACHA) can prevent cholesterol diet induced atherosclerosis. Our group is looking for the answer, whether ACHA have the same function in animals and in humans, or not. In this review we summarize our studies in human sera. We measured serum ACHA levels in different groups of patients with atherosclerotic diseases in patients with viral infections and in healthy population. In the summary we write about the possible functions of ACHA in the human immune system.