It has been noticed at the Stange Memorial Clinic that the incidence of canine leptospirosis has been steadily increasing. Definite diagnosis of this condition has not been established in all suspected cases, but symptoms and post-mortem lesions commonly seen in this clinic often point to one or more of the various syndromes of the disease. The attention of the general practitioner especially is called to the role which this condition may be playing in the gastrointestinal disturbances of the canine. Many times gastrointestinal symptoms are the most spectacular ones shown, and unless the practitioner is aware of the possibility of leptospirosis, he may very easily make a mistaken diagnosis.