The most common leukemia in adults is which type?

• A. Chronic myeloid leukemia (CML)
• B. Chronic lymphocytic leukemia (CLL)
• C. Acute myeloid leukemia (AML)
• D. Acute lymphoblastic leukemia (ALL)

Answer: (B)

Chronic lymphocytic leukemia is the most common leukemia in adults. It arises from mature B lymphocytes and often has an indolent, slow-growing course, so many cases are diagnosed in older individuals, sometimes incidentally during routine blood tests. Because the adult population—especially those over 60—has a higher burden of this disease compared to other leukemia types, it accounts for the largest share of adult leukemias.

In contrast, acute leukemias like acute myeloid leukemia and acute lymphoblastic leukemia are more common in children and can present with rapid symptoms, but they don’t occur as frequently as CLL in the adult population. Chronic myeloid leukemia is less common than chronic lymphocytic leukemia in adults. So when asked about the most common leukemia in adults, the best answer is chronic lymphocytic leukemia.