One hundred ninety patients, 61 with acute renal failure and 129 with chronic renal failure, underwent hemodialysis using a total of 302 subclavian vein catheters. Local hematomas and sepsis (seven events) were the only acute complications. Subclavian vein stenosis and/or thrombosis had occurred and were shown in five of 44 patients who had arteriovenous access created distal to the venous outlet obstruction, resulting in the loss of three of five of these accesses. In view of the fact that subclavian vein stenosis or occlusion is not associated with any clinical findings and we were unable to identify any predisposing factors associated with the use of the catheters, all patients who have had previous subclavian vein catheters probably should be evaluated to determine the patency of the subclavian vein before creation of a permanent access in that arm.