Megaloblastic anemia is a decrease in the amount of oxygen-carrying substance (hemoglobin) found in red blood cells. A person with this condition has low numbers of abnormally large, immature red blood cells that do not function properly.

Megaloblastic anemia can be caused by a folate deficiency or vitamin B12 deficiency.

Medical care for megaloblastic anemia is based on identifying and treating the cause of the anemia.