This retrospective study in the internal medicine department of the national teaching hospital of Ouagadougou was conducted to identify the main causes of iron-deficiency anaemia. Among the 65 subjects meeting the inclusion and exclusion criteria, mean haemoglobin was 7.5 g/dl, with mean serum ferritin 8.9 microg/l among women and 15.5 microg/l among men. The most common cause was chronic blood loss, and hookworm was a major cause in 19.6% of cases. These results suggest the need for preventive measures against iron deficiency and for reinforcement of the fight against diseases producing fecal blood loss.