What is the most common blood type?
O positive is the most common blood type in the world and in the United States, where about 37 to 38 percent of people have it. AB negative is the rarest of the main types.
Blood type frequencies vary a lot between populations. In the United States, the approximate breakdown is O positive about 37 percent, A positive about 36 percent, B positive about 8 percent, O negative about 7 percent, A negative about 6 percent, AB positive about 3 percent, B negative about 2 percent and AB negative less than 1 percent.
Type O is especially common among people of Latin American and Indigenous American ancestry. Type B is more common in parts of Asia, and Rh-negative blood is more frequent among people of European descent, especially the Basque people of Spain and France.
Why your type matters
Knowing your blood type is useful if you need a transfusion or are pregnant, because Rh-negative mothers carrying Rh-positive babies may need treatment to prevent complications. Common types are always in demand at blood banks because so many patients need them.
Did You Know?
Only a few dozen people worldwide are known to have Rh-null blood, a type with no Rh antigens at all, sometimes called golden blood.
This answer is general information, not medical advice. For a personal health question, talk to a doctor.