Anaemia is a common medical problem in elderly patients and is associated with an increased mortality and morbidity risk and a reduced quality of life. It is not known at which exact haemoglobin level investigations should be initiated in order to optimize the diagnostic efficacy. Serum ferritin determination remains the most accurate laboratory test for the diagnosis of iron deficiency anaemia and its differential diagnosis with the anaemia of chronic disease. The introduction of the metabolites methylmalonic acid and homocysteine has made it possible to diagnose vitamin B(12) and folate deficiencies at an early subclinical stage, even without neurological and haematological symptoms, but the clinical importance of this 'biochemical' diagnosis is unclear. Other causes of anaemia, such as myelodysplastic syndromes and chronic renal insufficiency, will become more and more common in the elderly because of the ageing of the population. Although erythropoietin analysis has no clear diagnostic value at the moment, it has become more and more obvious that its therapeutic importance in elderly patients with chronic anaemia is increasing. A substantial number of patients have an unexplained anaemia. Whether this is disease related, or may be attributed to an age-related anaemia, is still a matter of debate, but it is advisable to perform an extensive laboratory, cytogenetic, and morphological investigation before one should assess the anaemia as unexplained.