In july 1956 a long-term study of cerebral vascular disease was undertaken at Bellevue Hospital. Encouraged by the earlier writings of Fisher and Cameron (1), Millikan, Siekert, and Shick (2, 3), Denny-Brown (4), Kubik and Adams (5), Adams (6), Foley and Wright (7), and Wright and McDevitt (8), and aware of the need to establish the natural history of patients with cerebral vascular disease, the study group developed a protocol with both broad and limited objectives. This paper reports certain characteristics of a group of patients with strokes studied at a large municipal hospital. It presents a detailed analysis of