In the past decade I frequently have had anxious patients with thrombo-angiitis obliterans ask the question What is the outlook in my case? Hence the title of this paper. In an attempt to answer the question in such a manner that it may be of some service both to patients and to fellow workers in the field, I have carefully reviewed all the cases of thrombo-angiitis obliterans that have been observed at the Mayo Clinic from 1907 to 1937 inclusive. I have myself observed and studied a large number of these cases. The past decade has witnessed marked changes in the attitude of physicians toward thrombo-angiitis obliterans largely because of a better understanding of the disease. Prior to this time the diagnosis of thrombo-angiitis obliterans carried with it the implication that amputation of one or both lower extremities would follow inevitably and, once the diagnosis had been established, it was suggested that amputation of the involved extremity be carried out promptly. For example