SummaryThe author reports the case of a women, age 30, with chronic regional ileitis of the terminal part of the ileum.Surgical operation consisted in resection of the diseased part of the ileum and the lower end of the cæcum and in a termino-lateral anastomosis between the small intestine and the cæcum. It was followed by recovery. Pathological examination showed the usual lesions of Crohn’s disease. Bacteriological examination revealed in a mesenteric gland a coli type bacillus, which, after inoculation to test animal did not produce any intestinal alteration.In connection with this case the author mentions the results obtained in chronic ileitis by surgery, mainly resection in one or two stages, or entero-anastomosis with exclusion of the diseased loop.