Malabsorption has miscellaneous clinical and biological presentations. They may vary according to the site of the absorption abnormality (luminal, parietal, vascular transport), its type and severity. The problem of the physician is to become alerted to the possibility of malabsorption in patients who present with signs and symptoms which may be the concern of almost any specialist beside gastroenterologists. Patient history, type of signs and symptoms, physical examination and simple biochemical and haematological parameters may be of major interest in this regard and will help in the choice of the functional tests to perform. They will confirm the presumed malabsorption, precise its type and severity and may guide towards its aetiology, the precise diagnosis of which will usually require other investigations.