The investigation of iron deficiency should be oriented by clinical background. In group at risk (infants and children, women of childbearing age, pregnant women) management is limited to nutritional inquiry and gynaecologic examination and oral iron treatment. In men and post menopausal women iron deficiency is assumed to be the result of occult gastro-intestinal blood loss; so, in these patients, upper and lower gastro-intestinal endoscopy are required. Benign lesions are more frequently found in upper digestive tract than lower digestive tract. When these investigations are negative and iron treatment unsuccessful, enteroscopy is recommended. Oral iron treatment is performed with ferrous salts (200 mg/d). Duration of treatment depends on severity of iron deficiency: three months for iron stores deficiency an iron deficient erythropoisis, six months for iron deficiency anaemia.