Anemia in older adults is a risk factor for numerous negative outcomes. There is no standard definition, but in most studies, anemia is defined as a hemoglobin value <12 g/dL for women and <13 g/dL for men. Absolute iron deficiency anemia is defined as the combination of anemia and the absence of total body iron. Serum ferritin is the most frequently used diagnostic parameter, but its concentration increases with age and in the presence of inflammatory diseases. Other laboratory tests, such as transferrin saturation, soluble transferrin receptor and the soluble transferrin receptor/ferritin index might provide useful information, but there is a wide variety in the cut-off values and interpretation of the results. Recent research regarding hepcidin as a central regulator of iron homeostasis is promising, but it has not been used yet for the routine diagnosis of iron deficiency anemia. In older iron deficiency anemia patients, an esophagogastroduodenoscopy and colonoscopy should be initiated in order to identify the underlying bleeding cause. CT colonography can replace a colonoscopy, and in specific cases, a video capsule is recommended. It remains crucial to keep in mind which potential benefits might be expected from these investigations in this vulnerable population, taking into account the comorbidity and life expectancy, and one should discuss in advance the possible therapeutic options and complications with the patient, a family member or a proxy. Oral iron administration is the standard treatment, but parenteral iron is a convenient and safe way to provide the total iron dose in one or a few sessions. Geriatr Gerontol Int 2018; 18: 373-379.