Antigens in the ABO blood group system, besides being expressed on the surface of red blood cells, it is also expressed on other cell surfaces such as white blood cells, gastrointestinal epithelium cells, and platelets. From previous studies, it has been found that the expression on these cell surfaces affects various diseases, including infectious diseases and chronic non-communicable diseases (NCDs) as well, resulting in the rate of various diseases in each blood type being unequal. From searching and collecting many research papers from various databases, it was found that people with blood type A and blood type O have a greater risk of infection with the SAR-CoV2 that causes COVID-19 than people with other blood types, while in chronic non-communicable diseases it was found that people with the O blood type have a greater a risk of developing diseases such as high blood pressure coronary heart disease less than people with other blood types. There are also studies that have found that the ABO blood type affects the behavior of food choices. This may be another reason for the occurrence of various diseases as well. In this research article has also studied role of ABO antigen expression in various disease mechanisms.