At the annual session of the Société belge d'urologie, Drs. De Grave and Philippart presented a communication on colibacilluria. The terms "colibacilluria" and "urinary colibacillosis" should be applied only to the frank and permanent presence of considerable numbers of nonpyogenic colon bacilli in the urine of a living person. Colibacilluria may be due to an extra-urinary focus, often located in the prostate or the intestine, in which case it may be called a sustained colibacilluria. Colibacilluria may, on the other hand, be independent of any extra-urinary focus and may then be termed an "autonomous colibacilluria." The persistent character of autonomous colibacilli is due to an anatomic or physiologic impairment of the regular function of the excretory organs. Only an etiologic diagnosis and localization of the disorder will permit a rational form of treatment. Chemical and biologic treatment may supplement each other, but at present chemotherapy is more successful.