Of 30 patients with CLL examined with gastroscopy and 18 with additional coloscopy two showed lymphocytic infiltration of the stomach as well as of the large intestine, one of the stomach, and two of the large intestine only. The lymphocytic infiltration seems to depend more on tumor burden and proliferation activity than on stage. These results also make evident that conventional staging according to Rai or Binet without current diagnostic methods does not reflect the real extent of disease. However, it remains open to decide which patients are candidates for an endoscopic investigation and whether the proof of a gastrointestinal involvement results in a particular therapeutic consequence.